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The fluorides of platinum and related compounds Lohmann, Derek Harry 1961

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THE  FLUORIDES OF PLATINUM  and  r e l a t e d compounds by  DEREK HARRY LOHMANN B.Sc, M.Sc,  U n i v e r s i t y o f London, 1953 Queen's U n i v e r s i t y , O n t a r i o , 1959  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF  THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n t h e Department of CHEMISTRY  We a c c e p t t h i s t h e s i s as c o n f o r m i n g required  THE  to the  standard.  UNIVERSITY OF BRITISH COLUMBIA O c t o b e r 1961,  In presenting  t h i s thesis i n p a r t i a l f u l f i l m e n t of  the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available f o r reference and study.  I further agree that- permission  for extensive copying of t h i s thesis f o r scholarly purposes may granted by the Head of my Department or by his  be  representatives.  It i s understood that copying or publication of t h i s thesis f o r f i n a n c i a l gain s h a l l not be allowed without my written permission.  Department of  CHEMISTRY  The University of B r i t i s h Columbia, Vancouver 8, Canada. Date  31st October  1961.  %\\t Pntesttg of ^irtttslj Columbia FACULTY OF GRADUATE STUDIES  PROGRAMME OF THE FINAL ORAL  EXAMINATION  FOR T H E DEGREE OF  DOCTOR OF PHILOSOPHY oi  PUBLICATIONS . I. "Polar effects in Hydrogen abstraction reactions," M . P. Godsay, D. H . Lohmann and K. E. Russell, Chem. and Ind., 1959, 1603. 2. "Two new fluorides of Platinum," N. Bartlett and D. H. Lohmann, Proc. Chem. Soc, 1960, 14.  TUESDAY, NOVEMBER 28th, 1961, A T 1:00 P.M.  3. "The reaction of 2,2-Diphenyl-l-Picrylhydrazyl with 9,10-Dihydroanthracene and 1,4-Dihydronaphthalene,"  DEREK H A R R Y L O H M A N N B.Sc, University of London, 1953 M.Sc, Queen's University, Ontario, 1959  I. S. Hogg, D. H.  IN ROOM 342, CHEMISTRY  BUILDING  Lohmann and K. E. Russell, Canad. J. Chem., 1961, 39, 1394. 4. "The kinetics of reaction of 2,2-Diphenyl-l-Picrylhydrazyl with phenols," I. S. Hogg, D. H. Lohmann and K. E. Russell, Canad. J. Chem. 1961, 39, 1588.  COMMITTEE  IN  CHARGE  Chairman: F. H . SOWARD N. BARTLETT K. B. H A R V E Y L. D. H A Y W A R D  C. A . McDOWELL V. J. OKULITCH E. TEGHTSOONIAN  External Examiner: H . J. EMELEUS Cambridge University  T H E FLUORIDES OF PLATINUM A N D RELATED COMPOUNDS ABSTRACT The fluorides of platinum have been reinvestigated. Attempts to prepare a difluoride were unsuccessful. It is suggested that this is due to it being unstable towards disproportionation. X-ray Crystallographic evidence is presented as evidence for a trifluoride of platinum although a pure sample has not been isolated. This trifluoride is shown to be isostructural with the rhombohedral trifluorides of palladium, iridium and rhodium. Platinum tetrafluoride has been reinvestigated. It was found to be diamagnetic and to have a lattice of slightly-distorted, tetragonal uranium tetrachloride type. The adducts of platinum tetrafluoride with bromine trifluoride and selenium tetrafluoride were investigated further and found to be diamagnetic. The platinum tetrafluoride, selenium tetrafluoride adduct was shown to be isostructural with the corresponding palladium and germanium compounds. An ionic lattice is suggested for these compounds. Bromine trifluoride adducts do not form a similar series and this, combined with their physical properties, led to the suggestion that these compounds are more covalent in nature. The previously unknown pentapositive state of platinum has bein established. Platinum pentafluoride is a deep-red, reactive solid which readily disproportionates on heating. It gives rise to 1:1 adducts with iodine pentafluoride and chlorine trifluoride. These, like the bromine trifluoride adducts, are low-melting solids. Potassium fluoroplatinate (V) was prepared as a deep-yellow solid, crystallizing with the rhombohedral potassium fluorosmate lattice. A pentapositive oxyfluoride, platinum oxytrifluoride, was found; it is suggested that this is polymeric. Platinum hexafluoride has been briefly investigated. A very reactive oxyfluoride, of formula PtO„F 6 , has been prepared and investigated. It is a deep-red solid which can be sublimed at 90° in a vacuum. It melts with decomposition at 219°. It is paramagnetic and crystallizes in a cubic lattice. Many of its chemical properties were studied. It is suggested that this compound is platinum peroxidehexafluoride.  The crystal structures of the tetrafluorides of platinum rhodium, tin and lead were investigated. No similarity in structure was found. A brief investigation into the fluorides of rhodium has led to the suggestion that a pentafluoride, in addition to a terafluoride, exists.  G R A D U A T E STUDY Field of Study: Chemistry Topics in Inorganic Chemistry  N. Bartlett, H . C. Clark, W. R. Cullen, G. J. Willis  Advanced Inorganic Chemistry Crystal Structures Molecular Structure Seminar in Chemistry  N. Bartlett, H. C. Clark K. B. Harvey, L. W. Reeves  L. W. Reeves, C. Reid, J. Trotter N. Bartlett, K. B. Harvey  Other Studies: Differential Equations  C. Froese  Digital Computers  H . Dempster  Nuclear Physics  J. B. Warren  ,1  British  Columbia  * REQUEST * Transaction Number  4642692  Patmn Name  P a L r M . Number Item Number  39424050651303  Lille  Fluorides of platinum and related coi Pickup Location I.K. BARBER circulat Q g t o / T i mp  (ii)  ABSTRACT The  fluorides  prepare due  o f p l a t i n u m have b e e n . r e i n v e s t i g a t e d .  a d i f l u o r i d e were u n s u c c e s s f u l .  Crystallographic  trifluoride  of platinum  This t r i f l u o r i d e trifluorides  and  bromine t r i f l u o r i d e  these  adduct and  The  selenium  w i t h the  been r e i n v e s t i g a t e d .  of platinum  tetrafluoride platinum  rhombohedital  I t was  An  Bromine t r i f l u o r i d e  were i n v e s t i g a t e d  ionic adducts  combined w i t h t h e i r - p h y s i c a l  w i t h the lattice do  Platinum  corresponding i s suggested  n o t form  a  prepared  potassium  to  o x y t r i f l u o r i d e was Platinum  the  are low-melting  lattice.  found,  solid,  solids.  Potassium  adducts the  which with  bromine  fluoroplatinate  with the  rhombohedral  A pentapositive oxyfluoride, platinum  i t i s suggested  h e x a f l u o r i d e has  t o 1:1  These, l i k e  crystallizing  been  reactive solid  I t gives r i s e  chlorine t r i f l u o r i d e .  as a d e e p - y e l l o w  fluorosmate  for  similar-  properties lead  p e n t a f l u o r i d e i s a deep-red,  i o d i n e p e n t a f l u o r i d e and adducts,  further  compounds a r e more c o v a l e n t i n n a t u r e .  r e a d i l y d i s p r o p o r t i o n a t e s on h e a t i n g .  trifluoride  with  seleniumi t e t r a -  p r e v i o u s l y unknown p e n t a p o s i t i v e s t a t e o f p l a t i n u m has  established.  found  tetrafluoride  tetrafluoride,  isostructural  germanium compounds.  this,  n o t been, i s o l a t e d .  rhodium.  adducts  The  shown* t o be  suggestion that these The  type.  and  was  compounds.  s e r i e s and  isostructural  for a  t o have a l a t t i c e o f s l i g h t l y - d i s t o r t e d , t e t r a g o n a l  t o be d i a m a g n e t i c .  palladium  was  that this is-  as e v i d e n c e  a p u r e sample has  i s shown t o be  uranium t e t r a c h l o r i d e  fluoride  although  i s presented  t e t r a f l u o r i d e has  be d i a m a g n e t i c  found  evidence  o f p a l l a d i u m , i r i d i u m i and  Platinum  and  I t i s suggested  t o i t b e i n g u n s t a b l e towards d i s p r o p o r t i o n a t i o n . X-ray  to  Attempts to  been b r i e f l y  that t h i s  i s polymeric.  investigated.  (v)  (iii)  A very reactive oxyfluoride, and  investigated.  90°  i n a vacuum.  I t i s a deep-red  were s t u d i e d .  i n a cubic  prepared  s o l i d w h i c h c a n be s u b l i m e d a t  I t melts with decomposition! a t 219°.  m a g n e t i c and c r y s t a l l i z e s properties  o f f o r m u l a P t O ^ F g , has been  lattice.  I t i s suggested  that  I t i s para-  Many o f i t s c h e m i c a l t h i s compound  i s platinum  peroxidehexafluoride. The tin  crystal structures  of the t e t r a f l u o r i d e s of platinum  and l e a d were i n v e s t i g a t e d .  No  similarity  rhodium,  i n s t r u c t u r e was  found.  A b r i e f i n v e s t i g a t i o n i n t o t h e f l u o r i d e s o f rhodium has l e a d to; the suggestion! t h a t  a pentafluoride,  i n addition to a t e t r a f l u o r i d e , exists.  (iv)  TABLE OF CONTENTS ABSTRACT TABLE OF CONTENTS L I S T OF TABLES L I S T OF FIGURES L I S T OF PLATES ACKNOWLEDGEMENTS INTRODUCTION  Page i i iv vi v i i v  i  i  viii 1  EXPERIMENTAL ANALYSIS PHYSICAL METHODS MATERIALS APPARATUS FOR HANDLING FLUORINE FLUORINATION REACTIONS PLATINUM DIFLUORIDE PLATINUM TRIFLUORIDE PLATINUM TETRAFLUORIDE THE PLATINUM TETRAFLUORIDE, BROMINE TRIFLUORIDE ADDUCT . . THE PLATINUM TETRAFLUORIDE, SELENIUM TETRAFLUORIDE ADDUCT PLATINUM PENTAFLUORIDE POTASSIUM FLUOROPLATINATE (V) THE PLATINUM PENTAFLUORIDE, IODINE PENTAFLUORIDE ADDUCT. . THE PLATINUM PENTAFLUORIDE, CHLORINE TRIFLUORIDE ADDUCT. . PLATINUM OXYTRIFLUORIDE PLATINUM HEXAFLUORIDE P t O „ F PLATINUM PEROXIDEHEXAFLUORIDE? 2 o Preparation, Purification Properties Crystal Structure Mass s p e c t r u m I n f r a — r e d spectrum. . . . . . . . . . . . . U l t r a v i o l e t and v i s i b l e spectrumi Magnetic study Vapour p r e s s u r e s t u d y . . . . . . . . . Reactions  11 18 20 25; 26 30 31 32 39 39 44 46 50 50 52 53  RHODIUM TETRAFLUORIDE RHODIUM PENTAFLUORIDE? POTASSIUM FLUORORHODATE (V) TIN TETRAFLUORIDE LEAD TETRAFLUORIDE  66 69 70 72 75.  c  53 55 56 5:7 59 59 60 60 61 61  Page DISCUSSION THE VALENCY STATES OF PLATINUM PLATINUM DI FLUORIDE PLATINUM TRIFLUORIDE PLATINUM TETRAFLUORIDE . . . PLATINUM PENTAFLUORIDE POTASSIUM HEXAFLUOROPLATINATE (V) PLATINUM OXYTRIFLUORIDE PLATINUM HEXAFLUORIDE PtO F PLATINUM PEROXIDEHEXAFLUORIDE? THE COMPLEXES OF QUADRIPOSITIVE PLATINUM THE TETRAFLUORIDES THE FLUORIDES OF PALLADIUM THE FLUORIDES OF RHODIUM GENERAL DISCUSSION SUGGESTIONS FOR FURTHER INVESTIGATIONS  7.6 79 82 84 87 90 92 93 94 100 103 106 107 108 109  SUMMARY SUMMARY OF THE KNOWN FLUORIDES OF PLATINUM  110  APPENDICES 1. 2.  AN ALT/AC H I E COMPUTER PROGRAMME FOR THE DETERMINATION OF USEFUL FUNCTIONS FROM X-RAY POWDER PHOTOGRAPHS. . . AN ALWAC H I E COMPUTER PROGRAMME FOR THE GRAPHICAL DETERMINATION OF ACCURATE L A T T I C E PARAMETERS FOR TETRAGONAL CRYSTALS  REFERENCES  1  1  2  1  1  1  1  2  1  (vi)  L I S T OF TABLES Page TABLE I .  Tbe s i m p l e f l u o r i d e s  TABLE I I .  C a l c u l a t e d and o b s e r v e d x - r a y d i f f r & c t i o m data f o r platinum, t r i f l u o r i d e .  TABLE I I I .  TABLE I V .  10  •  31  C a l c u l a t e d and o b s e r v e d x - r a y d i f f r a c t i o m data f o r platinum t e t r a f l u o r i d e .  36  C a l c u l a t e d and o b s e r v e d x - r a y data f o r P t F (SeF )  diffractiom 41  C a l c u l a t e d and o b s e r v e d x - r a y data f o r PdF. ( S e F „ ) 4 4' 2  diffraction.  C a l c u l a t e d and o b s e r v e d x - r a y d a t a f o r GeF^ ( S e F )  diffractiom  C a l c u l a t e d and o b s e r v e d x - r a y d a t a f o r KPtF„ 6  diffraction  C a l c u l a t e d and o b s e r v e d x - r a y d a t a f o r JPtO- F„ 2 o  diffraction  4  TABLE V.  o f Group V I I I  4  2  42  0  TABLE V I .  4  TABLE V I I .  TABLE V I I I .  43  2  49)  58  TABLE I X .  Mass spectrum  TABLE X.  Infra-red  TABLE X I .  Molar  TABLE X I I .  C a l c u l a t e d and o b s e r v e d x - r a y d a t a f o r RhF^  diffractiom  Calculated  diffraction  TABLE X I I I .  o f PtOgEg  spectrum  59  of PWgFg  susceptibilites  60  o f PtO F  60  68  and o b s e r v e d x - r a y  data f o r SnF  x 10 " c . g . s . u n i t s  73  4  TABLE X I V .  Unit cell  dimensions  of the t r i f l u o r i d e  TABLE XV.  Knowm p e n t a f l u o r i d e s o f t h e second  o f Group  VIII83  and t h i r d  transition series  87  TABLE X V I .  Potassium  90  TABLE X V I I '  Lattice  TABLE X V I I I . TABLE XLX.  s a l t s , o f t h e MF ~ i o n  c o n s t a n t s o f some KMF s t r u c t u r e s o The known s a l i n e t e t r a f l u o r i d e s I n f r a - r e d s p e c t r a o f some t e t r a f l u o r i d e s C  . . . .  91 104 1  0  5  )  .•  (vii)  L I S T OF FIGURES Fo11owing page FIGURE 1.  Apparatus used  FIGURE 2.  Apparatus  FIGURE 3.  A p p a r a t u s f o r r e a c t i o n s i n v o l v i n g bromine t r i f l u o r i d e ? selenium, t e t r a f l u o r i d e or iodine pentafluoride . . . »  27  A p p a r a t u s f o r r e a c t i o n s i n v o l v i n g oxygem d i f l u o r i d e j sulphur t e t r a f l u o r i d e o r chlorine t r i f l u o r i d e . . . . . . . . . . . . .  28  FIGURE 4.  FIGURE 5:.  f o r pyrohydrolysis  f o r handling  . . . . . .  fluorine  Apparatus used f o r s t u d y i n g  11  . .  25s  thermal  decomposition r e a c t i o n s  33  FIGURE 6.  Apparatus used  f o r preparation  o f PtO^Fg  FIGURE 7.  A p p a r a t u s u s e d f o r p u r i f i c a t i o n , o f PtOgFg  FIGURE 8.  Apparatus used f o r measuring  gas e v o l u t i o n  . .  53  ...  55,  .  61  L I S T OF PLATES P L A T E 1.  Platinum t r i f l u o r i d e  PLATE 2.  Some T e t r a f l u o r i d e s  P L A T E 3.  P o t a s s i u m F l u o r o p l a t i n a t e (V)  82 1  0  3  91  (Vi i i)  ACKNOWLEDGEMENTS The for  author wishes  t o e x p r e s s h i s s i n c e r e a p p r e c i a t i o n t o B r . N. B a r t l e t t ,  h i s encouragement and h e l p f u l  d i s c u s s i o n , throughout  t h e course o f t h i s  study. The spectraj  author  i s grateful  t o M r s . M. Z e l l  f o r a s s i s t a n c e w i t h some o f t h e  t o D r . J . B l o o r and t h e B r i t i s h C o l u m b i a  o f t h e P e r k i n - E l m e r 21 s p e c t r o p h o t o m e t e r t o D r . D. F r o s t  employing  Research caesium  and Mr. F». B l o s s f o r t h e mass s p e c t r o m e t e r  C o u n c i l f o r use bromide  opticsj;  a n a l y s e s and to;  M e s s r s . H. Dempster and W. B e t w e i l e r o f t h e Computing C e n t r e f o r h e l p f u l d i s c u s s i o n on computer The  author thanks  programming. t h e C o n s o l i d a t e d M i n i n g and S m e l t i n g Company o f  Canada L i m i t e d f o r t h e award o f t h e COMINCO F e l l o w s h i p f o r 1960-61.  INTRODUCTION  The  h i s t o r y of inorganic f l u o r i n e  chemistry  falls  into three  distinct  phases:1)  The i s o l a t i o n o f e l e m e n t a l  o u t by M o i s s a n , 2)  e x p l o r a t o r y work  i n fluorine  chemistry  since the early  by t h e s e p a r a t i o n o f t h e i s o t o p e s o f u r a n i u m as t h e i r  hexafluorides. generator  and non  f l u o r i d e s by R u f f and h i s a s s o c i a t e s , between 1910 and 1935.  The renewed i n t e r e s t  initiated  carried  between 1886 and 1900.  The s y s t e m a t i c i n v e s t i g a t i o n o f a wide r a n g e o f m e t a l l i c  metallic 3)  f l u o r i n e and e a r l y  1940's, volatile  T h i s l e d t o t h e d e v e l o p m e n t o f a s a f e and r e l i a b l e  of f l u o r i n e  and more r e c e n t l y t o t h e a v a i l a b i l i t y  of f l u o r i n e  commercially. I n v e s t i g a t i o n o f t h e s i m p l e f l u o r i d e s o f p l a t i n u m was s t a r t e d by Moissan.  I n 1 8 8 9 ( l ) , he r e p o r t e d p l a t i n u m t e t r a f l u o r i d e and i n 1 8 9 1 ( 2 ) ,  platinum d i f l u o r i d e .  The e x i s t e n c e o f t h e former  substantiated, but the existence of the l a t t e r Moissan wire, heat  prepared  i n the presence went t h r o u g h  is still  of f l u o r i n e .  He f o u n d  or f l u o r s p a r boats*  t h e i n t e r m e d i a t e compound P t F ^ , nHF. remained behind  of platinum  to a dull-red  t h a t t h e r e a c t i o n proceeded  o f h y d r o g e n f l u o r i d e g a s , and s u g g e s t e d  platinum d i f l u o r i d e  questionable.  p l a t i n u m t e t r a f l u o r i d e by h e a t i n g b u n d l e s  contained i n thick-walled platinum i n a stream  compound has been w e l l  better  that the reaction  Moissan  claimed t h a t  a s an i n s o l u b l e r e s i d u e when t h e t e t r a -  f l u o r i d e was e x t r a c t e d w i t h w a t e r , b u t gave no a n a l y t i c a l  evidence t o support  this. Subsequent r e p o r t s of t h e p r e p a r a t i o n o f p l a t i n u m t e t r a f l u o r i d e b e e n made by R u f f  and Z e d n e r ( 3 ) ,  o x y g e n o r n i t r o g e n i n an e l e c t r i c  who h e a t e d  a mixture  have  o f f l u o r i n e and  d i s c h a r g e between p l a t i n u m e l e c t r o d e s .  2  Buff(4) obtained  i t by h e a t i n g t h e compound PbF^,  platinum vessel; dull  by t h e a c t i o n  red heat(5)  and,  fluoride  was  fluorine  t o above 200  in a  on p l a t i n u m m e t a l  at a  t o g e t h e r w i t h p l a t i n u m d i f l u o r i d e , as a t h i n  on t h e p l a t i n u m anode when bifluoride,  of f r e e  3HF  liquid  electrolysed(6).  hydrogen f l u o r i d e , t r e a t e d Sharpe(7) prepared  with  platinum  by h e a t i n g t h e compound P t B r g F ^ Q t o a t e m p e r a t u r e  layer potassium  tetra-  of 200° under  vacuum. Platinum several  tetrafluoride  also  been r e p o r t e d as a b y - p r o d u c t  f l u o r i n a t i o n r e a c t i o n s performed  Attempts to prepare  the r e a c t i o n  ( 2 , 13,  Moissan  on p l a t i n u m  between m o l t e n p o t a s s i u m  Attempts to prepare 14,  volatile  and  and  t o decompose a t r e d h e a t  silicon tetrafluoride.  o f p h o s p h o r o u s and b e e n found  tetrafluoride(l6). = 1.1  12)  or  as d i d  metal(ll).  aqueous s o l u t i o n  have  as a d a r k r e d mass and  c r y s t a l s w h i c h needed t o be  into  fluorine  also  platinum  I t dissolves  readily  d i o x i d e of platinum, I t readily  to  adducts  Nyholm and  into  metal.  Bohr m a g n e t o n s ) .  platinums  hydrofluoric  t h i s decomposition  combines w i t h t h e f l u o r i d e s  is  chlorides  compounds.  r e p o r t e d i t as b e i n g  acid  greatly  and  w i t h bromine t r i f l u o r i d e ( 7 ) and  Sharpe(l7)  be  i n water t o g i v e  boron to give w e l l - c r y s t a l l i n e v o l a t i l e t o form  as  sealed  I t i s said  and  w h i c h decomposes e x o t h e r m a l l y  the orange, hydrated  also  of l i q u i d  i n a g l a s s tube, the g l a s s i s a t t a c k e d to produce  a c c e l e r a t e d by b o i l i n g .  has  10).  15).  a yellow-brown s o l u t i o n and  from  in  ( 8 , 9,  (ll,  platinum  glass vessels for their preservation.  When i t i s h e a t e d metal  failed  b i f l u o r i d e and  described platinum t e t r a f l u o r i d e  well-dried,  apparatus  by t h e a c t i o n  tetrachloride  platinum t e t r a f l u o r i d e  s m a l l , brown-yellow, very hygroscopic in  i n platinum  platinum t e t r a f l u o r i d e  gaseous hydrogen f l u o r i d e  failed  has  It  seleniumi  paramagnetic  3.  Claims  t o hare prepared  the d i f l u o r i d e  workers other than Moissan. i n a stream Ruff(6)  o f hydrogen f l u o r i d e t o a temperature  potassium  Platinum that and  P o u l e n c ( l 2 ) heated  c l a i m e d t o have p r e p a r e d  when l i q u i d  bifluoride  difluoride  i s insoluble fluorine.  Little  platinum d i f l u o r i d e  platinum Malm(l9).  weights, only other  else  i s known about i t .  described  crust  t h a t some (l,  2)  ( P t F I g ) " and With the r e v i s i o n  corrected(l8)).  d e s c r i b e d r e c e n t l y by W e i n s t o c k , C l a a s e n and this  by e l e c t r i c a l l y  heating a platinum  a t a p r e s s u r e o f 300  o f t h e r e a c t i o n was p l a t i n u m t e t r a f l u o r i d e ?  was c o o l e d w i t h l i q u i d  nitrogen.  chemical  as a d a r k - r e d  i t s massive form.  electrolysed.  f l u o r i d e o f p l a t i n u m r e p o r t e d h i t h e r t o , was t h e v o l a t i l e  condensed on a s u r f a c e ? d i r e c t l y  described  (PtFl)".  anode  platinum  due t o M o i s s a n  as " p l a t i n u m b i f l u o r i d e  t h i s was s u b s e q u e n t l y  They p r e p a r e d  h e x a f l u o r i d e by  of 300°.  ( i t is felt  i n the early l i t e r a t u r e  as a n o n - v o l a t i l e , y e l l o w - b r o w n s o l i d . solid  i n excess  2) as a g r e e n i s h - y e l l o w  as " p l a t i n u m p r o t o f l u o r i d e  hexafluoride,  main product  fluoraplatinate  c o n t a i n i n g h y d r o g e n f l u o r i d e was  i n a n atmosphere o f f l u o r i n e gas m a i n t a i n e d The  ammonium  i n water and w h i c h on h e a t i n g decomposes i n t o  describing platinum t e t r a f l u o r i d e  The  have b e e n made by  i t as a t h i n l a y e r on t h e p l a t i n u m  i s described ( l ,  c o n f u s i o n may have a r i s e n  o f atomic  of platinum  In addition,  mm.  which remained  a yellow-brown,  above t h e p l a t i n u m  spiral,  which  a n a l y s i s and v a p o u r d e n s i t y measurements.  solid  volatile  T h i s compound was shown t o be p l a t i n u m  o f m e l t i n g p o i n t 56.7° t h a t appears  I t s v a p o u r i s brown-red, s i m i l a r  as t h e l e a s t  spiral  t o bromine.  It is  black ini I t was  s t a b l e and most r e a c t i v e o f t h e t h e n known h e x a -  f l u o r i d e s , s l o w l y decomposing when s t o r e d i n g l a s s o r q u a r t z ? red-brown r e s i d u e , which t h e authors  s t a t e must be due e i t h e r  leaving a t o photo-  4.  decomposition  or t o r e a c t i o n  indefinitely,  a t room t e m p e r a t u r e ,  s o l i d was  r e p o r t e d t o be  fluorides  b u t no X - r a y  with the g l a s s . i n clean  f i n d that  those observed  d a t a has  been p u b l i s h e d .  of  history  was  The  first  made by B e r z e l i u s ( 2 l ) , who  by t r e a t i n g  a s o l u t i o n of potassium  quantity of c h l o r o p l a t i n i c potassium  chloroplatinate  ammonium s a l t  acid, and  induce c r y s t a l l i z a t i o n .  to in:  b a c k beyond  that  fluoroplatinate(lV)  decanting the l i q u i d Berzelius  Schlesinger  and  f i n e l y divided  equivalent  from t h e also  (22,  p l a t i n u m metal  (or K^PbEg) (HF )) , e x t r a c t i n g g  as l e a d  precipitated  prepared  co-workers  s u l p h a t e and  S h a r p e and Emeleus(24) p r e p a r e d  i n a platinum c r u c i b l e .  r u b i d i u m and  platinates  o r b r o m o p l a t i n a t e s w i t h bromine t r i f l u o r i d e .  co-workers(26, They f i r s t  27,  caesium  Sharpe(7,  potassium,  acid.  are s i m i l a r  the 23) with  with  48$  evaporating  potassium  i n low y i e l d by t h e t h e r m a l d e c o m p o s i t i o n o f p o t a s s i u m i  tetrafluorobromite  and  infra-red  f l u o r i d e with a l e s s than  s a l t by f u s i n g 4  authors(20)  being interpreted  prepared potassium  a c i d , p r e c i p i t a t i n g the lead  fluoroplatinate  i n the  hexa-  of s a l t s of f l u o r o p l a t i n i c  evaporating.  t h e complex f l u o r i d e 3KF.HF.PbF  to  same  of platinum;goes  report  i n a s i m i l a r manner.  prepared the potassium  hydrofluoric  spectrum  iridium  The  0^.  group  o f t h e complex f l u o r i d e s  the simple f l u o r i d e s .  acid  The  f o r t h e other, known h e x a f l u o r i d e s ,  stored  containers.  t h e main f e a t u r e s of the spectrum  terms o f t h e o c t a h e d r a l p o i n t The  nickel  i s o s t r u c t u r a l w i t h osmium and  have s u b s e q u e n t l y o b s e r v e d t h e v i b r a t i o n a l r e g i o n , and  I t c a n however be  28,  29)  s a l t s by t r e a t i n g  were t h e f i r s t  prepared a s e r i e s  of r a r e  25)  prepared  the corresponding Pernos,  the chloro-  Naeserr  to i s o l a t e f l u o r o p l a t i n i c earth fluoroplatinates,  by  5.  heating the corresponding rare stream  earth f l u o r i d e with platinum f o i l  o f d r y a i r t o a temperature  o f 525°  f o r f i v e hours  and l e a c h i n g  t h e w a t e r - s o l u b l e r a r e - e a r t h f l u o r o p l a t i n a t e from t h e m i x t u r e . a c i d was p r e p a r e d by p a s s i n g an aqueous s o l u t i o n o f lanthanum  The f r e e fluoroplatinate  t h r o u g h a column o f Dowex 50 ( s t r o n g a c i d ) i o n exchange r e s i n , r a t i n g the e l u a t e t o dryness over  i n a p o l y e t h y l e n e beaker  sodium h y d r o x i d e p e l l e t s .  s o l u b l e potassium,  and evapo-  by vacuum d e s i c c a t i o m  The same a u t h o r s p r e p a r e d t h e s p a r i n g l y  r u b i d i u m and c a e s i u m  actions of the corresponding a l k a l i s o l u t i o n , the s a l t s being p u r i f i e d  s a l t s by s i m p l e m e t a t h e t i c a l r e -  n i t r a t e w i t h lanthanum  fluoroplatinate  by r e c r y s t a l l i z a t i o n from h o t w a t e r .  Sodium and ammonium f l u o r o p l a t i n a t e were p r e p a r e d by " t i t r a t i n g " fluoroplatinate  s o l u t i o n with the corresponding hydroxide  more lanthanum h y d r o x i d e p r e c i p i t a t e d . centrifuged  ina  lanthanum;  s o l u t i o n u n t i l no  The lanthanum h y d r o x i d e was  o f f , t h e s o l u t i o n e v a p o r a t e d a l m o s t t o d r y n e s s under  reduced  p r e s s u r e and c o o l e d t o 5 ° u n t i l  p r e c i p i t a t i o n was c o m p l e t e .  prepare l i t h i u m  i n a s i m i l a r manner were u n s u c c e s s f u l as  fluoroplatinate  hydrolysis of the fluoroplatinate i o n occurred. strontium oxide>  Attempts t o  Magnesium, c a l c i u m and  s a l t s were p r e p a r e d by t h e r e a c t i o n o f f l u o r o p l a t i n i c  h y d r o x i d e and c a r b o n a t e o f t h e r e s p e c t i v e m e t a l s .  s o l u b l e barium  acid with the  The s p a r i n g l y  s a l t was p r e p a r e d by t h e m e t a t h e t i c a l r e a c t i o n o f lanthanum  f l u o r o p l a t i n a t e w i t h barium Fluoroplatinic  acid  chloride.  i s o b t a i n e d i n t h e h y d r a t e d form and c o n s i s t s o f  yellow, hygroscopic crystals  (27).  I t st i t r a t i o n  s o l u t i o n shows i t t o be a s t r o n g a c i d .  c u r v e w i t h sodium* h y d r o x i d e  The s a l t s o f f l u o r o p l a t i n i c  acid  are a l l p a l e y e l l o w i n colour;  those o f t h e r a r e eaths, a l k a l i n e earths;  (with the exception of barium),  sodium and ammonium a r e s o l u b l e i n water  6.  and t h o s e o f p o t a s s i u m , Potassium crystal  r u b i d i u m , caesium  and  barium  are  insoluble*  f l u o r o p l a t i n a t e has been shown t o be d i a m a g n e t i c ( l 7 ) .  The  s t r u c t u r e s o f t h e s e compounds, as i n d e e d w i t h many compounds o f  t h e t y p e A^MXg, c o n s i s t o f c l o s e - p a c k e d l a y e r s o f A and X atoms w i t h t h e M atoms o c c u p y i n g some o f t h e o c t a h e d r a l h o l e s (30> arrangement o f t h e f l u o r i n e s complete  silicate,  w h i c h has  r u b i d i u m and  caesium  structure.  The  The  s t r o n t i u m and b a r i u m  a b s o r p t i o n spectrum  unit  cell  (22, 2 6 ) .  p o t a s s i u m i (25, potassium  The u l t r a v i o l e t  The  infra-red  3,  slowly ( 7 ) .  a t 583  g e t t i n g no By  I t has  been found d i f f i c u l t  of r e d u c i n g agents  i o n to the f l u o r o p l a t i n i t e  cm  of  The  potassium! note  a  fluoroplatinate (this  is in  fluoropalladate  ion)  t o reduce  the f l u o r o p l a t i n a t e i o n ,  i s precipitated.  Perros et al(35)  i n attempting to reduce the  fluoro-  i o n , b u t t h e y were u n s u c c e s s f u l , e i t h e r ,  r e d u c t i o n a t a l l or g e t t i n g  estimating the electrode p o t e n t i a l s ,  other  the  s u b s t i t u t i o n r e a c t i o n s with the other halogem a c i d s only v e r y  a wide v a r i e t y  platinate  on  visible  ( 3 4 ) , who  s t a b l e (22, 3 5 ) , b e i n g s t a b l e t o h y d r o l y s i s  but when r e d u c t i o n does o c c u r p l a t i n u m m e t a l tried  and  a b s o r p t i o n spectrum  marked c o n t r a s t t o t h e r a p i d h y d r o l y s i s o f t h e r e l a t e d and u n d e r g o i n g  fluorogermanate  shown t o have maxima a t  by P e a c o c k and S h a r p J  fluoro-  32)  s a l t s have been i n t e r p r e t e d  (33).  s i n g l e maximum, w h i c h t h e y a s s i g n , as is relatively  The  o f t h e f l u o r o p l a t i n a t e i o n was  f l u o r o p l a t i n a t e has b e e n m e n t i o n e d  ion  i s isomorphous w i t h sodium  structure.  the  f l u o r o p l a t i n a t e by M e l l o r  compounds have t h e t r i g o n a l  basis of a rhonbohedral  318 m/u  sodium s a l t  a hexagonal  The o c t a h e d r a l  t h e p l a t i n u m has b e e n shown by  s t r u c t u r e determination of potassium  and Stephenson, ( 3 2 ) .  245? and  around  31).  complete  reduction to platinum metal.  by e x t r a p o l a t i o n from t h o s e o f t h e  complex h a l i d e s o f p l a t i n u m i n aqueous s o l u t i o n , t h e y c o n c l u d e d  that  7.  the f l u o r o p l a t i n i t e  i o n i s probably  t i o n a t i o n i n t o p l a t i n u m metal  unstable with respect to dispropor-  and t h e f l u o r o p l a t i n a t e  ion.  o t h e r complex f l u o r i d e s o f p l a t i n u m known were t h e bromine and  selenium  tetrafluoride(16)  w h i c h c o u l d be p r e p a r e d  adducts  The o n l y trifluoride(7)  of platinum t e t r a f l u o r i d e ,  both of  by t h e i n t e r a c t i o n o f p l a t i n u m t e t r a f l u o r i d e  with  the a p p r o p r i a t e s o l v e n t . The  f o r e g o i n g has b r i e f l y  summarized t h e known f l u o r i d e s o f p l a t i n u m  b e f o r e t h e p r e s e n t work was s t a r t e d . t h a t time  a r e compared w i t h t h o s e  T a b l e 1.  We  we go from  left  valency  of higher valency  i n any one t r i a d  s t a t e s decreases  and t h a t t h e s t a b i l i t y  s t a t e s i n c r e a s e s w i t h t r a n s i t i o n s e r i e s number.  two s t a b l e f l u o r i d e s ,  a difluoride  f l u o r i d e i s r e a d i l y reduced useful  o f t h e o t h e r group V I I I e l e m e n t s i n  see t h a t t h e s t a b i l i t y to right  The f l u o r i d e s o f p l a t i n u m known a t  as a f l u o r i n a t i n g  and a t r i f l u o r i d e ;  as  of higher  Thus, i r o n  forms  i n cobalt, the t r i -  t o t h e v e r y s t a b l e d i f l u o r i d e and i s t h e r e f o r e  agent;  t h e o n l y known s i m p l e  f l u o r i d e of n i c k e l  is the d i f l u o r i d e . I n t h e second  triad,  ruthenium  pentafluoride also a t r i f l u o r i d e  a t t a i n s the highest valency i n forming  ( 3 6 , 37) and i n a d d i t i o n , R u f f  have r e p o r t e d t h e d o u b t f u l e x i s t e n c e o f r u t h e n i u m  octafluoride  f l u o r i d e s o f r h o d i u m have b e e n e s t a b l i s h e d , t h e t r i f l u o r i d e tetrafluoride  (33, 7 ) .  R u f f and A s c h e r  compound t h e y had p r e p a r e d was t h e t e t r a f l u o r i d e  (36).  Two  (38) and t h e  c o u l d n o t e s t a b l i s h whether t h e  by t h e a c t i o n o f f l u o r i n e on rhodium a t 5 0 0 °  or t h e p e n t a f l u o r i d e , but Sharpe(7),  r h o d i u m t e t r a f l u o r i d e by t h e a c t i o n o f bromine t r i f l u o r i d e tetrabromide  and V i d i c  has s t a t e d t h a t t h e p r o p e r t i e s o f t h i s  who  prepared  on rhodium  compound a r e i d e n t i c a l  a  8..  with those given is  the highest  have b e e n w e l l Bartlett  by R u f f  and A s c h e r  (38).  known s i m p l e f l u o r i d e . established  In palladium,  The d i f l u o r i d e and t h e t r i f l u o r i d e  ( 3 8 , 39) b u t i t was n o t u n t i l  and Hepworth t h a t p a l l a d i u m  the t r i f l u o r i d e  t h e work o f  d i f l u o r i d e was o b t a i n e d  i n t h e pure  state. In the t h i r d  triad,  s t a b i l i t y decreases fluoride  i n the order  o f osmium r e p o r t e d  W e i n s t o c k and Malm  is  by R u f f  Ruff  a tetrafluoride, their  and T s c h i r c h  (40) has been shown by  (43) i s t h e o n l y  as b e i n g  the pentafluoride.  established oxyfluoride  and h e x a f l u o r i d e  of i r i d i u m are well  s i m i l a r i t y between t h e p r o p e r t i e s  hexafluoride  Osmium t r i o x y -  o f t h e g r o u p , though an  by R u f f  has s i n c e been d e n i e d by R o b i n s o n and W e s t l a n d  tetrafluoride  a  identical  by t h e n a t u r e o f i t s p r o p e r t i e s ?  o x y t e t r a f l u o r i d e o f i r i d i u m had been c l a i m e d this  The o c t a -  and T s c h i r c h had a l s o r e p o r t e d  "hexafluoride',  here t e n t a t i v e l y assigned  difluoride  osmium, i r i d i u m , p l a t i n u m .  ( 4 l ) and by H a r g r e a v e s and P e a c o c k (42) t o be  with the hexafluoride. and  a l t h o u g h a l l t h e m e t a l s form h e x a f l u o r i d e s , t h e  and F i s c h e r (45).  The  (44), but trifluoride,  e s t a b l i s h e d , though t h e  o f t h e t e t r a f l u o r i d e and n e i g h b o u r i n g  penta-  f l u o r i d e s had b e e n n o t e d ( 4 5 ) . W i t h t h e complex f l u o r i d e s > this  respect  i r o n i s somewhat; anomalous i n t h a t  complexes. pentavalent  complexes, t h e r e m a i n d e r o f t h e t h i r d a l l f o r m i n g t h e MF^  t h e o n s e t o f t h i s work t h e n ,  series of platinum-fluorine characterized  and t h e h e x a v a l e n t  i t does n o t form  t r a n s i t i o n s e r i e s from  ion.  several  compounds.  though i n  i t does n o t form t e t r a v a l e n t  P l a t i n u m t o o seems somewhat anomalous i n t h a t  tantalum to platinum At  t h e same t e n d e n c i e s a r e n o t i c e d ,  gaps r e m a i n e d i n t h e e x p e c t e d  The t e t r a v a l e n t s t a t e was  s t a t e had o n l y  j u s t been  well  established.  9 .  The  divalent  s t a t e had  b e e n r e p o r t e d but n o t  state, very  stable  as p l a t i n u m  i n i t s valence  t h e g r o u p , had and  i t was  shell  n o t been r e p o r t e d .  r u t h e n i u m and  ingly,  i n p a l l a d i u m w h i c h has  possibly  decided  and  confirmed.  the  exhibited The  The  trivalent  same e l e c t r o n i c  structure  by most o f t h e members o f  pentavalent  i r i d i u m , a g a i n had  state,  shown by  n o t been r e p o r t e d .  osmium Accord-  t o r e i n v e s t i g a t e t h e f l u o r i d e s of p l a t i n u m w i t h  view to t r y i n g to prepare  and  characterize  t h o s e t h e n unknown v a l e n c y  a states.  10  TABLE I The S i m p l e F l u o r i d e s o f Group  VIII  Iron  Cobalt  Nickel  FeF^  CoF  2  NiF,  FeF,  CoF  3  Ruthenium  Rhodium  Palladium PdF  RuF,  RhF„ RhF m.l06°,  RuF_  2  PdF„  4  b.313°  RuF (?) g  Platinum  Iridium  Osmium  PtF (?) 2  IrFg OsF  4  m.230°,  0sF (?) m.70°, 5  OsF. o OsOgFg  b.280-300°  PtF,  b.225.5°  m.32.1°,b.45.9°  m.170  I r F ^ m.l06-lo7°, b.300° 4 IrF  m.44  c  Ir0F (?) 4  ,  b.53.6  P t F - m.56.7 o  EXPERIMENTAL  11.  ANALYSIS AH  w e i g h i n g s were p e r f o r m e d u s i n g a M e t t l e r  load balance. were c a r r i e d  Unless otherwise stated, o u t on m e d i u m - p o r o s i t y ,  a g e n t s were o f ANALAR g r a d e .  "Gramatic", constant-  a l l quantitative  sintered-glass  Standard a n a l y t i c a l  filtrations  crucibles.  The r e -  t e c h n i q u e s were  followed  throughout ( 4 6 ) . INTRODUCTION The  a n a l y s i s o f p l a t i n u m f l u o r i d e s was c o m p l i c a t e d by t h e f o r m a t i o n  in  s o l u t i o n of the stable f l u o r o p l a t i n a t e  or  fluorine  down. (1)  c o u l d be e s t i m a t e d q u a n t i t a t i v e l y t h i s  The f o l l o w i n g a n a l y t i c a l  Willard  schemes e f f e c t e d  and W i n t e r d i s t i l l a t i o n  A known w e i g h t  of m a t e r i a l )  acid  was d i s t i l l e d  and (2)  and  (47) was  f l a s k and 25 m i s . o f c o n c e n t r a t e d  from a d r o p p i n g f u n n e l .  were c o l l e c t e d .  The m i x t u r e  A p p r o x i m a t e l y 200 m i s . o f  The f l u o r i n e was r e c o v e r e d as h y d r o f l u o r i c  acids.  Pyrohydrolysis  ( 4 8 , 49)  a p p a r a t u s used was s i m i l a r t o t h a t d e s c r i b e d by e a r l i e r  i s shown i n F i g u r e 1.  silica  this:-  w i t h t h e t e m p e r a t u r e k e p t i n t h e r a n g e 130-135? by t h e  fluorosilicic  The  i o n had t o be b r o k e n  60fi p h o s p h o r i c a c i d were added.  or p r e f e r a b l y  a d d i t i o n o f water distillate  Before either platinum  c o n t a i n i n g 0.05. t o 0.3g. o f f l u o r i n e ,  added t o a l o n g - n e c k e d d i s t i l l a t i o n sulphuric  (IV) i o n .  workers  The e s s e n t i a l p a r t o f t h e a p p a r a t u s was a  t u b e , 2 cm. d i a m e t e r and 40 cm. l o n g , h a v i n g a 35/20 B.S.  s o c k e t a t one end and a B.10 ground  silica  cone a t t h e o t h e r .  silica The steam  c o n d e n s e r , o f P y r e x g l a s s , was a t t a c h e d t o t h i s by way o f a B.10 ground  cone.  FIGURE 1  Apparatus used for pyrohydrolysis  12.  The  steam p r e h e a t e r and steam t r a p , made o f ^ i n . i n t . diam. copper t u b i n g ,  were a t t a c h e d t o t h e o t h e r end o f t h e s i l i c a m a c h i n e d t o f i t t h e 35/20 B.S. s i l i c a t h e B.10 s i l i c a  furnace.  Essentially,  in a 1 litre,  three-necked  flask;  b u b b l e r , one t h e m o i s t - a i r / s t e a m o u t l e t and  of the conditions w i l l  be f o u n d under t h e compounds  a p l a t i n u m b o a t was weighed t o c o n s t a n t w e i g h t  h e a t e d t o 3 0 0 ° i n a stream t u r e i n a stream  o f hydrogen.  The f l u o r i d e  transferred  The  b o a t was q u i c k l y t r a n s f e r r e d  The h y d r o l y s i s was c a r r i e d  o v e r t h e sample a t 3 0 0 ° .  the condenser  o u t by f i r s t  the temperature  the bubbler together with the temperature  by b u b b l i n g t h r o u g h 50 m i s .  and t h e b o a t  reweighed.  t o the p y r o h y d r o l y s i s tube, i n i t i a l l y a t  o v e r t h e sample, t h e n s l o w l y r a i s i n g  steam was p a s s e d  being  sample, a p p r o x i m a t e l y 0.2 g,  t o t h e p l a t i n u m boat i n a dry-box  room t e m p e r a t u r e .  after  concerned.  o f steam f o l l o w e d by h e a t i n g t o t h e same tempera-  was  from  i n an  a thermometer.  Details  air  The p y r o h y d r o l y s i s t u b e was h e a t e d  Steam was g e n e r a t e d  neck t a k i n g t h e a i r i n l e t  the t h i r d  B o t h t h e b r a s s b a l l and  T e m p e r a t u r e measurements were made u s i n g a h i g h tempera-  t u r e thermometer. one  socket.  ball,  cone were p r o v i d e d w i t h i n s e t t u b e s t o p r e v e n t t h e o c c u r -  r e n c e o f seepage a t t h e j o i n t s . electric  t u b e by means o f a b r a s s  passing moist  o f t h e water i n .  of the furnace u n t i l  eventually  The d i s t i l l a t e was c o l l e c t e d  o f water c o n t a i n e d i n a c o n i c a l  were c o l l e c t e d w i t h t h e d i s t i l l a t e .  flask.  Washings  The f l u o r i d e i o m  c o n c e n t r a t i o n was e s t i m a t e d by t i t r a t i o n w i t h 0.1 N sodium h y d r o x i d e u s i n g p h e n o l p h t h a l e i n as i n d i c a t o r . tion  s h o u l d be c a r r i e d  t h i s was f o u n d  Earlier  w o r k e r s (48) c l a i m e d t h a t t h e t i t r a -  o u t a t 6 0 ° t o decompose any f l u o r o s i l i c i c : a c i d , b u t  t o be a n u n n e c e s s a r y p r e c a u t i o n .  _  fo F  T i t r a t i o n ( m i s . ) x 0.19 Wt. o f sample ( g . )  13.  To  check t h e t i t r a t i o n ,  the fluoride  i o n was p r e c i p i t a t e d  as l e a d  chlorofluoride. To d e t e r m i n e 10 mm.  platinum,  t h e c o n d e n s e r was r e p l a c e d by a s i l i c a  d i a m e t e r t a p e r i n g t o 5 mm.  diameter.  w i t h n i t r o g e n , t h e n h y d r o g e n was p a s s e d , The  boat For  weighing (3}  bottle  fitted  to constant  t h e p l a t i n u m i b o a t was c o n t a i n e d i n a h o r i z o n t a l with a c l o s e - f i t t i n g  ground g l a s s  transferred  inside  t o a 02 g e l a t i n e  an i r o n s h i e l d  allowed  and h e a t e d  f o r 1 h r . over  t o c o o l t o room t e m p e r a t u r e ,  Reduction  with absolute ethyl  0.2 g. o f m e t a l l i c  alcohol.  the m e t a l . success.  A variety  recommended;  a Meker b u r n e r .  The bomb;  sodium was d e s -  The f l u o r i n e was e x t r a c t e d , as l e a d  chlorofluoride.  t o t h e p r e c i p i t a t i o n o f p l a t i n u m as  o f r e d u c i n g agents  Beamish i n h i s r e v i e w  agents,  I t was p l a c e d  methods  R e d u c t i o n methods g e n e r a l l y l e a d  have been t r i e d  p r e c i p i t a t i o n i s never  complete,  r e d u c t i o n with z i n c metal  some z i n c becomes p l a t i n u m  with varying  (52) s t a t e s t h a t when u s i n g o r g a n i c r e and t h e s e  a r e n o t t o be  i n hydrochloric acid  a q u a n t i t a t i v e p r e c i p i t a t i o n of platinum metal, taken,  The c a p s u l e was  then t h e excess  sodium f l u o r i d e , w i t h water and e s t i m a t e d  ducing  0.1 g. o f f l u o r i n e  The bomb, was screwed t o g e t h e r i n t h e dry-box:.  t r o y e d by b o i l i n g  (4)  capsule in. a dry-box.  i n s i d e a P a r r bomb t o g e t h e r w i t h a p p r o x i m a t e l y  sodium.  as  stopper.  P a r r bomb method ( 5 0 , 51)  placed  was  burned.  weight.  A known w e i g h t o f m a t e r i a l c o n t a i n i n g a p p r o x i m a t e l y was  was f l u s h e d  t h e emergent gas b e i n g  and p l a t i n u m . r e s i d u e were h e a t e d a l l weighings,  The a p p a r a t u s  tube  s o l u t i o n gives;  b u t u n l e s s extreme c a r e i s  coated l e a d i n g t o a high  result.  14.  Conclusion The the  Willard  W i n t e r method and  disadvantage that  o n l y one  suffers  distillation, results  due  The was  pretreatment. of  component can  method a l s o  and  and  to  and  be  the  estimated at  from t h e  acid  precipitation  ESTIMATION OF  sample i s n e c e s s a r y and  a time.  The  of  Willard  lead  and  from  that:, Winter  bumping o f t e n o c c u r s  i s u s e d t h i s can  p y r o h y d r o l y s i s method does n o t u s e d whenever  r e d u c t i v e methods s u f f e r  disadvantage that  when s u l p h u r i c  the  the  lead  to  during  erronious  sulphate. suffer  from t h e s e  disadvantages;  possible.  FLUORINE  Introduction Fluorine  may  calcium fluoride or  lead  using  be  e s t i m a t e d by  (53),  chlorofluoride  sodium a l i z a r i n The  nitrate  lithium (56)  i s very d i f f i c u l t  gives a precipitate cipitation  as  that  lithium  and  Precipitation  triphenyltin  the  e s t i m a t i o n must be  carefully controlled relies  largely  cipitate the  on  conversion factor  triphenyltin fluoride  (47)  are  the  t i t r a t i o n of  filter  and  gives a w e l l - c r y s t a l l i n e  conversion factor fluoride  conditions.  i n this  suffers  settles readily i s favourable.  most common.  empirical and  as  wash. and  thoriumi  fluoride Pre-  easily  case i s not  from t h e  Precipitation  adherence to  solution  P r e c i p i t a t i o n with calcium to  filter-  favourable.  disadvantage solution  lead  as (55)  f l u o r i d e with  p e r f o r m e d i n a 60-70^ a l c o h o l i c  a rigid  i s granular,  indicator  i s very d i f f i c u l t  but  which p r e c i p i t a t i o n  t i t r a t i o n with thorium n i t r a t e  to detect.  fluoride  the  (54),  p o i n t i n the  able p r e c i p i t a t e as  fluoride  s u l p h a t e as  y e l l o w t o p i n k end  many methods, o f  that  under  chlorofluoride  procedures, but  is easily filtered.  Accordingly this last  the In  preaddition,  precipitation  15.  method was u s e d this  exclusively  f o r the estimation of the f l u o r i d e i o n i n  investigation.  E s t i m a t i o n o f f l u o r i n e by p r e c i p i t a t i o n as l e a d The  distillate  from e i t h e r  a pyrohydrolysis  chlorofluoride o r from a W i l l a r d and  W i n t e r d i s t i l l a t i o n was made j u s t a l k a l i n e t o bromophenol b l u e w i t h sodium h y d r o x i d e s o l u t i o n .  Concentrated hydrochloric  acid,  1 m l . , was  added and t h e s o l u t i o n h e a t e d t o 80°; l e a d n i t r a t e , 5 g . , was added stirring solved  and t h e h e a t i n g was c o n t i n u e d u n t i l  and t h e s o l u t i o n was j u s t below b o i l i n g p o i n t .  5 g . , was added w i t h s t i r r i n g , chlorofluoride.  a sintered-glass  chlorofluoride  overnight.  Because o f t h e p o s s i b i l i t y  of  lead  quantities  solution of lead o f water.  The p r e -  Wt. o f P b C l F x 7.261 Wt. o f Sample  of p r e c i p i t a t i n g other  ions  under  these  p a r t i c u l a r l y when t h e s o l u t i o n t o be e s t i m a t e d was t h e d i s -  from a W i l l a r d  sulphuric  f o r one hour  t o c o n s t a n t weights a t 1 3 0 — 1 4 0 ° . =  tillate  acetate,  The p r e c i p i t a t e was c o l l e c t e d  c r u c i b l e , washed w i t h a s a t u r a t e d  j* F l u o r i n e  conditions?  Sodium  r e s u l t i n g i n the precipitation*, of lead  and f i n a l l y w i t h two s m a l l  c i p i t a t e was d r i e d  with  n i t r a t e had d i s -  The heavy, w h i t e p r e c i p i t a t e was d i g e s t e d  a t 9 5 - 1 0 0 ° and a l l o w e d t o c o o l on  a l l the lead  lQfi  acid,  chlorofluoride  and W i n t e r d i s t i l l a t i o n p e r f o r m e d i n t h e p r e s e n c e  i t was t h e p r a c t i c e  t o check t h e c o m p o s i t i o n o f t h e  by d i s s o l u t i o n i n d i l u t e n i t r i c  c i p i t a t i o n of the chloride  as s i l v e r =  Fluorine  acid  f o l l o w e d by p r e -  chloride. Wt. o f A g C l x 13.26 Wt. o f Sample  ESTIMATION OF PLATINUM Introduction Any as m e t a l  o f t h e methods m e n t i o n e d e a r l i e r from  the fluoroplatinate  f o r the p r e c i p i t a t i o n of platinum  i o n may be u s e d  p l a t i n u m w i t h t h e r e s e r v a t i o n s made t h e r e . that there i s incomplete  f o r the estimation o f  The c l a i m o f Beamish  (52),  p r e c i p i t a t i o n o f p l a t i n u m when u s i n g o r g a n i c r e -  ducing agents,  h a s b e e n s u b s t a n t i a t e d i n t h i s work.  granular  added s l o w l y , f o l l o w e d by w a s h i n g o f t h e p r e c i p i t a t e d  zinc,  Reduction with  fine,  p l a t i n u m w i t h 10^ h y d r o c h l o r i c a c i d g i v e s q u a n t i t a t i v e p r e c i p i t a t i o n o f p l a t i n u m w i t h no c o n t a m i n a t i o n Other  methods u s e d  by t h e z i n c .  to estimate platinum  i n c l u d e , p r e c i p i t a t i o n as  p l a t i n u m d i s u l p h i d e ( 5 7 ) , p r e c i p i t a t i o n as ammonium h e x a c h l o r o p l a t i n a t e ( 5 8 ) , and  p r e c i p i t a t i o n as d i m e t h y l p h e n y l b e n z y l The  disadvantage  by t h e p r e c i p i t a t e ,  bromoplatinate  o f t h e s u l p h i d e method i s t h a t s u l p h u r i s o c c l u d e d  c a u s i n g an u n c e r t a i n t y o f composition.  as ammonium h e x a c h l o r o p l a t i n a t e s u f f e r s from precipitate  (59, 60).  Precipitation  the disadvantage  that the  i s a p p r e c i a b l y s o l u b l e i n water (0.5 g./lOO g . w a t e r )  (61),  t h i s may be o f f s e t t o some e x t e n t by p e r f o r m i n g t h e e s t i m a t i o n i n a s o l u t i o n c o n t a i n i n g an excess and  hence s o l u b i l i t y ,  o f ammonium c h l o r i d e .  o f compounds o f t h i s t y p e h a s b e e n found  c r e a s e d by i n c r e a s i n g t h e s i z e o f t h e a n i o n s . w i t h l a r g e a n i o n s were t r i e d c h l o r i d e was f o u n d this  t o be t h e most s a t i s f a c t o r y .  as t h e m e t a l  re-precipitating  with z i n c ,  from  t o be d e -  ammonium  Accordingly, s o l u t i o n by f i r s t  then d i s s o l v i n g t h e metal  as d i m e t h y l p h e n y l b e n z y l  energy,  A v a r i e t y o f compounds  (59) and d i m e t h y l p h e n y l b e n z y l  i n v e s t i g a t i o n p l a t i n u m was e s t i m a t e d  tating  The h y d r a t i o n  bromoplatinate.  throughout precipi-  i n aqua r e g i a and  17.  E s t i m a t i o n o f p l a t i n u m by p r e c i p i t a t i o n w i t h dimethylphenylbenzylammonium c h l o r i d e P r e p a r a t i o n of reagent  (62)  Dimethylphenylbenzylammonium quantities and  of f r e s h l y d i s t i l l e d  dimethyl  benzyl  a n i l i n e (191-194°) (31  E x c e s s r e a c t a n t s were removed by recrystallized, of  ethyl  the  as  acetate  A bf> solid.  was  (m.p.  116°  mis.)?  as  (176-178°) (28  equimolar  mis.)  a w h i t e c r y s t a l l i n e mass.  w a s h i n g w i t h e t h e r and  (sealed  the  from a l c o h o l  material by  the  was  addition  tube)).  a 0.1^>  B o t h were s t o r e d  p r e p a r e d , by m i x i n g  chloride  a white c r y s t a l l i n e s o l i d ,  aqueous s o l u t i o n and  many months  chloride  aqueous s o l u t i o n were p r e p a r e d  i n dark b o t t l e s  and  were s a t i s f a c t o r y  from after  storage.  Estimation A known q u a n t i t y of the  fluoroplatinate  and  fine?  The  precipitated  granular  i n a sintered and  dried The  to  a solution containing  i o n , was  zinc  I t was  amounts u n t i l  hydrochloric  reduction  a t 4 0 - 5 0 ° f o r one washed w i t h 10^  i n the  was  form acid  complete.  hour, then  hydrochloric  collected acid  c o n s t a n t w e i g h t at, 1 1 0 ° .  p l a t i n u m was  s o l u t i o n was  and  solid  dissolved  i n the  minimum q u a n t i t y  t w i c e e v a p o r a t e d t o d r y n e s s w i t h 48^  sodium b r o m i d e .  a c i d , 4 mis.  digested  crucible.  platinum, usually  t a k e n , made a c i d w i t h 10^  added i n s m a l l  p l a t i n u m was  glass  the  The  of  The  r e s i d u e was  dissolved  o f aqua r e g i a  hydrobromic  ammonium c h l o r i d e  d i l u t e d to per  10 mg.  100  mis.  and  5 mis.  o f 5/&  acid  i n hydrobromic  o f h y d r o b r o m i c a c i d b e i n g added f o r e a c h 10 mg.  s o l u t i o n was  and  of  platinum.  dimethylphenylbenzyl-  o f p l a t i n u m were added w i t h s t i r r i n g .  The  18.  f l o c c u l e n t , orange p r e c i p i t a t e was allowed to stand f o r 3 hours, and then c o l l e c t e d i n a s i n t e r e d - g l a s s c r u c i b l e , washed with the 0.1^ s o l u t i o n of dimethylphenylbenzylammonium c h l o r i d e followed by 3 mis. of dioxane and 4 mis. of cyclohexane.  The p r e c i p i t a t e was d r i e d to constant weight at 80°. Wt. of ppt. x 0.1776 Wt. of Sample  $ Pt.  The methods used i n the pretreatment of the compounds and estimation of other elements w i l l be mentioned under the compounds  concerned.  PHYSICAL METHODS X-ray powder photographs These were taken using n i c k e l - f i l t e r e d copper K 1.5443;  Mot, 1.5405;  r a d i a t i o n (K<* ,  K «=< (£ (2K<* + K«* )) , 1.5418 £ ) . X  2  The n i c k e l  filter,  0.089 mm. t h i c k , was placed i n the c o l l i m a t o r of a General E l e c t r i c model XRP-SF11 X-ray d i f f r a c t i o n u n i t and removed most of the Sy3 r a d i a t i o n . The d i f f r a c t i o n p a t t e r n was recorded p h o t o g r a p h i c a l l y using a 14.32 cm. camera of the Straumanis  type.  With the t a r g e t operated at 40 KV and 15 mA  r e q u i r e d exposure times v a r i e d between 4 and 20 hours. Specimen c a p i l l a r i e s , 0.5 mm. diameter, of e i t h e r quartz or Lindemann glass (as supplied by Pantak L t d . , Windsor) were used. m a t e r i a l s were loaded i n the dry box.  Hygroscopic  The c a p i l l a r i e s were sealed using  a small» hot flame and the seal was covered with p i c e i n wax. tances between symmetrical  The dis*-  p a i r s of arcs were measured using an accurate  .2 scale and v e r n i e r .  Bragg angles, i n t e r p l a n a r spacings, 1/d  2 values, s i n ©  values and the Nelson-Riley e x t r a p o l a t i o n f u n c t i o n (63) were obtained from these using an ALWAC I I I E d i g i t a l computer (Appendix were estimated v i s u a l l y .  I).  Intensities  19.  Magnetic Measurements Magnetic susceptibilities were measured using a Guoy balance? described i n detail by Clark and O'Brien (64).  The magnetic balance con-  sisted of a Varian 4-inch electromagnet, model Y4084, having 2-inch tapered pole caps? producing a f i e l d of approximately 15 kilogauss, with a current of 2 amperes.  The current was regulated by a Varian, model  U2300 A» power supply with model 2301 A current regulator.  Weighings  were made on a Spoerhase, Model 10M, microbalance having a sensitivity of - 0.01 mg.  Temperature control was provided by a cryostat similar  to that described by Figgis and Nyholm (65), which allowed the temperatur to be controlled at any point i n the range 78-300°K by suitable control o the current passing through an e l e c t r i c a l l y heated c o i l and the pressure within the inner Dewar flask. The sample, contained i n a glass tube 12 cms. x 5 mm.  was suspended  from the bottom of the sample pan, and between the pole pieces of the magnet,  by means of a thin gold chain.  f i e l d off and then with the f i e l d on. weighed.  The sample was weighed with the The tube was emptied and re-  This procedure was repeated with the tube f i l l e d with an. equal  volume of mercury ( i i ) cobaltitetr.athiocyanate (66). Magnetic moments were calculated using the formula.  Where, the subscripts I and II refer to sample and standard respectively. W &W  Weight of material Increase i n weight of the material i n the magnetic  field.  20.  A g  Gram s u s c e p t i b i l i t y  V  -6  A gll  16.4 x 10  c.g.s. u n i t s  T  Temperature (°K)  0  Curie Temperature  U l t r a - v i o l e t and v i s i b l e  spectra  U l t r a - v i o l e t and v i s i b l e spectra were recorded using e i t h e r a CARY 11 or a CARY 14 instrument.  In the s o l u t i o n work matched 1 cm. quartz c e l l s  were used. Infra-red  spectra  I n f r a - r e d spectra were recorded using e i t h e r a PERKIN ELMER "Infracord"' spectrophotometer or a PERKIN ELMER 21, spectrophotometer. S p e c i f i c G r a v i t y measurement S p e c i f i c g r a v i t i e s were measured using a 1 ml. capacity b o t t l e provided with a ground g l a s s cap. dry box.  Hygroscopic m a t e r i a l s were loaded i n the  Carbon T e t r a c h l o r i d e was employed on the displacement  fluid.  MATERIALS Platinum metals A l l platinum metals were obtained from Johnson, Matthey and M a l l a r y L t d . , Toronto, grades of at l e a s t 99.99^ p u r i t y being used. Fluorine F l u o r i n e was obtained from A l l i e d Chemicals, General Chemicals. D i v i s i o n , New York. Platinum-metal  salts  Ammonium H e x a c h l o r o p l a t i n a t e A l l residues and s o l u t i o n s from experiments were bulked together. P e r i o d i c a l l y , they were evaporated t o dryness and extracted with aqua r e g i a .  21.  Excess n i t r i c acid was removed by evaporating to dryness twice with concentrated hydrochloric acid.  The residue was dissolved i n concentrated  hydrochloric acid, diluted four times with water and treated with an equal bulk of saturated ammonium chloride solution.  The pale-orange precipitate  was allowed to settle overnight, f i l t e r e d , washed twice with saturated, ammonium chloride solution, and f i n a l l y with water. Found*  Pt, 43.95^  Calc. for (NH ) Pt C16:- Pt, 43.97^. 4  2  Hexachloroplatinic acid Hexachloroplatinic acid was prepared by treating a hot (80°) suspension of ammonium hexachloroplatinate with an excess of acid-washed Dowex 50 (strong acid) ion-exchange resin.  The conversion was completed  by passing the solution through a column of the same resin.  The golden-  yellow solution was evaporated to dryness under an i n f r a red lamp to give red-brown deliquescent crystals of hexachloroplatinic acid hexahydrate (m.p.  60°).  Found:  The crystals were recrystallized from water.  Pt, 38.21/&  Calc. for H PtC16, 6H 0: Pt, 37.70^. 2  2  Platinum Tetrachloride (67) Platinum tetrachloride was prepared by heating hexachloroplatinic acid to 275° i n a stream of chlorine for two hours, allowing to cool to 150°, grinding, re-heating to 275° for a further one hour and f i n a l l y allowing to cool i n a stream of nitrogen.  Platinum tetrachloride obtained  i n this manner consists of deep, red-brown, hygroscopic readily form the yellow pentahydrate.  I t was therefore stored i n sealed  tubes. Found:  Pt, 57.78^  crystals which  Calc. for PtCl4, 57.92^.  22.  Platinum Dichloride (68) Platinum dichloride was prepared by heating hexachloroplatinic acid to 450° i n a stream of chlorine for two hours.  The residue was;  boiled with a 0.5$ aqueous solution of hydrochloric acid, to remove any platinum tetrachloride, then dried at 360° for 30 minutes.  Platinum;  dichloride obtained i n this way was green brown. Found: Platinum  Pt, 73.22.  Calc. for PtCl :-  Pt, 73.36$,  Tetrabromide  Platinum tetrabromide was prepared by Halberstadt s modification of 1  the method of Meyer and Zublin (69, 70). Platinum sponge was heated to 180° i n a sealed tube with an excess of 2:1, hydrobromic acid (48$) : bromine, for 12 hours.  The solution was  f i l t e r e d , to remove any platinum dibromide, evaporated to dryness thenheated to 180°.  The residue was re-dissolved i n water and the evapo-  ration and drying repeated.  Platinum tetrabromide was obtained as deep  v i o l e t crystals. Found:  Pt, 54.95.  Calc. for PtBr :4  Pt, 55.0$.  Platinum Dioxide Platinum dioxide monohydrate was obtained by the method of Adams et a l . (71, 72, 73) A solution of 8 g. of hexachloroplatinic acid hexahydrate i n 20 mis. of water was added to 78 g. of sodium nitrate i n a s i l i c a evaporating basin.  The solution was heated slowly with constant s t i r r i n g .  At 300°,  the sodium nitrate melted and reacted with the hexachloroplatinic acid; resulting i n the evolution of nitrogen dioxide and the precipitation of platinum dioxide.  Heating was continued to 480°, and this  temperature  23.  was maintained for 15 minutes. was then leached with water.  The mixture was allowed to cool and The insoluble platinum dioxide was washed  f i r s t by decantation, then by f i l t r a t i o n , until free from nitrates.  It  was dried at 110°. The monohydrate was dehydrated by heating, 280°, i n a stream of oxygen for 48 hours. Found:  Pt, 85.38.  Calc. for Pt0 : -Pt, 85.92$. 2  Rhodium Trichloride Rhodium metal was heated to 600° i n a stream of chlorine for 24 hours. Rhodium trichloride prepared i n this way was a deep red-brown crystalline solid. Found:  Rh, 49.3.  Calc. for RhCl_:  Rh, 49.2$.  Rhodium tribromide Rhodium tribromide was prepared by refluxing rhodium metal with an excess of a bromine/faydrobromic acid mixture for 48 hours. bromine/hydrobromic  acid was d i s t i l l e d off at 15-20 mm.  solution was slowly evaporated under an infra-red lamp.  The excess  pressure and the The crystals  obtained were dried i n a vacuum desiccator to yield deep-red-violet crystals of rhodium tribromide dihydrate. Found:  Rh, 27.0.  Calc. for RhBr  3>  2H 0: 2  Rh, 27.2$.  Tin metal and lead acetate B r i t i s h Drug Houses ANALAR grade were used. Hafnium Metal Material of 99.9$ grade from Bios Laboratories Inc., New York, was used.  24.  Selenium Tetrafluoride Selenium tetrafluoride was prepared by the method of Aynsley, Peacock and Robinson (74). Selenium metal was sublimed on to the walls of a flask of approximately 2 l i t r e s capacity.  The flask was cooled to 0° i n an ice bath and the  selenium fluorinatedj using a low rate of flow of fluorine.  The seleniumi  tetrafluoride produced was condensed i n a train of traps cooled i n alcohol/ solid carbon dioxide.  P u r i f i c a t i o n was by trap to trap d i s t i l l a t i o n .  Sulphur Tetrafluoride Sulphur tetrafluoride was obtained from Du Pont and Nemours Inc., Wilmington. Bromine Trifluoride, Iodine Pentafluoride and Chlorine Trifluoride These were obtained from the Mattheson Co. Inc., Newark and were used after trap to trap d i s t i l l a t i o n . Oxygen Difluoride Oxygen difluoride was prepared by the method of Ruff and Menzel (75). Fluorine was slowly bubbled through 250 mis. of a 2$ aqueous sodium hydroxide solution, oxygeni difluoride together with some oxygeni was evolved. The gases were washed by bubbling through water, and water vapour and hydrogen fluoride were removed by passing the gases through a trap cooled to -78° i n alcohol/solid carbon dioxide.  Oxygen difluoride was  condensed  as a pale yellow l i q u i d i n a trap cooled to -183° by liquid oxygen.  The  reaction was allowed to proceed u n t i l approximately 5 mis. of oxygen d i fluoride had condensed.  The oxygen difluoride was; sealed off at atmos-  pheric pressure and stored at liquid oxygen temperature u n t i l needed.  25.  APPARATUS FOR HANDLING FLUORINE The apparatus that was used for handling fluorine i s shown diagrammatically i n Figure 2. fume-hood.  I t was contained i n a wide, well-ventilated  The cylinder was clamped i n a vertical position and shielded  on two sides by bricks and on the other sides by the walls of the fumehood.  The cylinder valve was opened by a key, which was welded to a  four-foot long handle manipulated  through a slot i n the brick shield.  The base of the valve was held firmly by means of a wrench attached to a four-foot handle. The pressure of the fluorine, which was 400 lbs. per sq. inch in the cylinder, was reduced by using two Hoke stainless-steel, needle valves in series.  The high-pressure side, which was constructed from half-inch,  stainless steel pressure tubing, was connected to the cylinder by a compression f i t t i n g , a teflon gasket being employed.  A stainless-steel)  Bourden-type, pressure gauge was screwed and silver-saldered into this part of the system.  The low pressure side was constructed from quarter-  inch copper tubing with the exception of the sodium fluoride-pellet: chamber, A, which was of half-inch diameter copper tubing.  A l l valves on the low-  pressure side of the system were brass-bodied, bellows-sealed needle valves. There was no flow meter i n the system, though an estimation of the rate of flow was obtained from the bubble rate i n the low-viscosity, fluorocarbon-oil (Hooker Chemicals, FS-5) blow-off.  Earlier attempts to  measure the flow rate using a pin-hole flow meter were unsuccessful due to blockage of the pin-hole. The sodium fluoride pellets served to remove any hydrogen fluoride contained i n the fluorine.  The diluent gas was dried by passage through  FIGURE 2  Apparatus for handling fluorine •3  o a. a. o  N  3  2"°2  H  K  ONI  26.  a Brechsel bottle containing sulphuric acid. Reaction systems were attached to the fluorine supply by means of "teflon" tubing ( i " i.d., f "  o.d.)  FLUORINATION REACTIONS In a l l fluorination reactions, the apparatus used must be dry, otherwise hydrolysis, with the consequent generation of hydrogen fluoride w i l l occur.  The avoidance of hydrolysis i s particularly important wheni working  in glass or s i l i c a systems, for the hydrogen fluoride produced then, reacts to produce silicontetrafluoride and water, which then generates more hydrogen fluoride.  This combination of reactions continues u n t i l the  material supplying the hydrogen, fluoride or the glass are consumed. Rigorous drying of the apparatus was achieved by heating the apparatus, while under vaccum, with a non-luminous flame.  When the system was to  be open to the atmosphere, nitrogen gas was admitted v i a a bubbler containing concentrated sulphuric acid and a trap cooled i n liquid oxygen. Reactions involving elemental fluorine In these reactions} the apparatus was dried and nitrogen gas, which was used as a diluent, introduced as described.  A single trap was attached  to the apparatus before the reaction zone? this was cooled with liquid oxygen to remove hydrogen fluoride and moisture from the fluorine/nitrogen mixture.  A train of traps was attached beyond the reaction zone, and  these too were cooled with liquid oxygen.  Liquid oxygen (b. -183°) was  the most suitable refrigerant as i t condensed most v o l a t i l e reaction*products but not fluorine (b. -188°).  Liquid nitrogen (b. -196°) i s less  suitable i n that i t does condense fluorine.  High temperature  fluorination  reactions i n glass or s i l i c a apparatus produced s i l i c o n tetrafluoride which  27.  also condensed i n the traps cooled with liquid oxygen.  In such cases,  i t was found more convenient to employ alcohol/solid carbon dioxide (-78°) cooled traps i n which s i l i c o n tetrafluoride did not  collect.  The reaction zone was heated by calibrated, wire-wound heaters* Reactions involving bromine t r i f l u o r i d e , selenium tetrafluoride or iodine pentafluoride These solvents have convenient liquid ranges (BrF , m. 9°, b. 126°,  o IF , m. 10°, b. 100°, SeF. , m. -10°, b. 100°) and can be handled easily in systems similar to that shown i n Figure 3. The solvent was be fluorinated  stored i n a break-seal bottle, 1.  The material to  or brought into solution was placed in a s i l i c a reaction  bulb, 2, which was attached to the system through a graded-seal. scopic materials were also placed i n break-seal bottles.  Hygro-  The loading  carried out i n a dry-box, and the bottles were sealed under vacuum.  was The  leading limb of trap 3 was constricted s l i g h t l y . In a typical procedure, the traps of the dried, apparatus were cooled with l i q u i d oxygen, them the break-seal was broken by moving the nickel balls with a magnet.  The l i q u i d oxygem was removed from around trap 1  and the contents were allowed to warm up, any ice condensing on the outside was removed by gentle warming using a hot-air blower.  The  first  material to d i s t i l condensed i n the constriction i n trap 3 forming a plug of solid which prevented further material d i s t i l l i n g into this trap. remainder of the material d i s t i l l e d smoothly into trap 2.  The  It was found  preferable not to heat trap 1 other than to remove the ice formed on the outside, otherwise attack on the glass occurred with the consequent formation of s i l i c o n tetrafluoride.  This caused a loss of vacuum which resulted i n  FIGURE 3  Apparatus for reactions involving bromine trifluoride. selenium tetrafluoride or iodine pentafluoride  a—-*  o  r—  o in o >N >  Wi  2Z&  28.  a decrease i n t h e rate of d i s t i l l a t i o n . When a l l t h e s o l v e n t had been t r a n s f e r r e d ?  the l i q u i d  oxygeni around  t r a p 3 was l o w e r e d and t h e p l u g removed by m e l t i n g w i t h a h o t - a i r The  s t o r a g e t r a p was removed by s e a l i n g t h e a p p a r a t u s a t " a " .  was  s l o w l y a d m i t t e d and t h e l i q u i d  r e a c t i o n bulb; temperature.  t h e r e a c t i o n b u l b was t h e n a l l o w e d t o warm up t o room The r e a c t a n t s were r e f l u x e d ? when n e c e s s a r y ? by warming t h e flame.  the  vessel  was c o o l e d w i t h l i q u i d  The  liquid  oxygen was removed from around  products d i s t i l l i n g  When r e a c t i o n was  complete?  oxygen and t h e system was r e - e v a c u a t e d .  s l o w l y warm up t o room t e m p e r a t u r e ? i n t o t r a p 3.  t h e b u l b ? which  was a l l o w e d t o  e x c e s s r e a c t a n t and any v o l a t i l e When t h e t r a n s f e r r e n c e was  complete?  b u l b was s e a l e d o f f a t " b " . E x c e s s bromine t r i f l u o r i d e  of  Dry a i r  oxygen was removed from around t h e  r e a c t i o n b u l b w i t h a small? luminous  the  blower.  d r y carbon t e t r a c h l o r i d e .  was d e s t r o y e d by p o u r i n g i n t o an e x c e s s E x c e s s e s o f s e l e n i u m t e t r a f l u o r i d e and  i o d i n e p e n t a f l u o r i d e were d e s t r o y e d by p o u r i n g i n t o a n e x c e s s o f concenrtrated into  sulphuric  acid.  This  s o l u t i o n was t h e n poured?  stream?  a copious q u a n t i t y o f water.  R e a c t i o n s i n v o l v i n g oxygen,, d i f l u o r i d e ? or  i n a thin  chlorine These  sulphur t e t r a f l u o r i d e  trifluoride compounds a r e n o t l i q u i d  a t room t e m p e r a t u r e  (SF^? m. -121°?  b . - 4 0 ° , QFg* m. - 2 2 4 ° , b . 1 4 5 ° , C l F g , m. -76°? b . 12°) and had t o be manipulated material  i n closed  systems?  t o be f l u o r i n a t e d  a c t i o n tube?  which  similar  t o t h a t shown i n F i g u r e 4.  was c o n t a i n e d i n a n i c k e l  boat i n s i d e the r e -  c o u l d be h e a t e d by means o f a wire-wound h e a t e r .  a p p a r a t u s was d r i e d ? t h e n the.  The  The  v o l a t i l e r e a c t a n t was t r a n s f e r r e d t o t r a p 1?  FIGURE 4  FIGURE k  Apparatus for reactions involving oxygen difluoride, sulphur tetrafluoride or chlorine trifluoride OJ t O  a  Q; I _ Ul  «- o a  4f  Z D CJ  vCM  ro  3 _a —  I  E E 3  OJ  o o  tn  >  0)  29.  which was cooled with liquid nitrogen, and the apparatus was sealed at "a" and "b".  Trap 4 was surrounded with l i q u i d nitrogen, and the re-  action zone was heated to the desired temperature.  Trap 1 was allowed  to warm up, with a consequent d i s t i l l a t i o n of the reactant through the reaction zone to trap 4.  The v o l a t i l e  reactant was transferred back  to trap 1 i n a similar manner, after f i r s t cooling the reaction zone to room temperature.  The temperature of the reaction zone was raised and  the above procedure repeated.  When the reaction was judged to be com-  plete, the excess of v o l a t i l e reactant was condensed into trap 2, which was then removed from the system by sealing at "c" and "d *. 1  Any non-  v o l a t i l e product and unreacted starting material were sealed into the reaction tube by sealing at "e . ,,;  Any v o l a t i l e product, not v o l a t i l e at  room temperature was retained i n trap 3 by sealing at " f " . Excess reactants were disposed of by allowing them to slowly evaporate i n a well-ventilated flume hood.  30.  PREPARATION AND PROPERTIES OF THE FLUORIDES OF PLATINUM PLATINUM DIFLUORIDE A l l attempts to reduce platinum tetrafluoride to prepare a lower fluoride of platinum were unsuccessful. Attempted fluorination of platinum dichloride using anhydrous hydrogen fluoride Platinum dichloride, contained i n a nickel boat, was heated i n a stream of anhydrous hydrogen fluoride i n a nickel reactor.  There was  no interaction at temperatures below 200° and the only identifiable products obtained at temperatures above this were platinum metal and platinum tetrafluoride. Reaction of platinum dichloride with sulphur tetrafluoride Platinum dichloride, contained i n a nickel boat, was reacted with sulphur tetrafluoride i n an all-glass, closed system.  I n i t i a l l y the  reaction was carried out at room temperature, then the temperature was raised i n 50° intervals.  No apparent reaction occurred up to a tempera-  ture of 400°, when fluorination of the containing tube occurred. An x-ray powder photograph of the residue revealed no lines other than those of platinum dichloride.  31.  PLATINUM TRIFLUORIDE A l l attempts to reduce platinum tetrafluoride to y i e l d a lower fluoride were unsuccessful.  However, x-ray powder photographs of the residues from  the fluorination of platinum metal i n the presence of powdered glass, at 400°j showed a pattern of lines that corresponded very closely to those of palladium t r i f l u o r i d e . These lines were indexed on the basis of a bimoleculor rhombohedral unit c e l l with a = 5.41 t 0.01A*, ^=54.3 £ 0.1°, V-97A* , Dc=8.6 g. cm" . 3  3  Calculated and observed values of l / d ^ are given i n Table I I . Residues from these reactions were inhomogeneous, consisting mainly of pale-yellow to orange material containing some black specks.  It i s  significant that specimens having the more intense platinum t r i f l u o r i d e pattern also contained a greater proportion of black material. TABLE I I .  Calculated and observed x-ray d i f f r a c t i o n data for platinum t r i f l u o r i d e . 1/jlf hkl  Calc.  Obs.  110 211 IOT 222 210 200 220 321 332 211 310  0.0760 0.1391 0.1648 0.1893 0.2121 0.2408 0.3039 0.3541 0.3914 0.4056 0.4687 0.4945 0.7331 0.8486  0.0775 0.1418 0.1666 0.1895 0.2121 0.2425 0.3064 0.3588 0.3973 0.4071 0.4702 0.4946 0.7295> 0.8483  211  431 420  32.  QUADRIPOSITIVE PLATINUM  PLATINUM  TETRAFLUORIDE,  PtF  4  Preparation 1.  F l u o r i n a t i o n of platinum  metal  F l u o r i n a t i o n o f platinum metal fluorine  a t 300° p r o d u c e d  action product. crystalline,  platinum  When, p r o d u c e d  Thermal d e c o m p o s i t i o n  bromine t r i f l u o r i d e (i)  t e t r a f l u o r i d e as t h e n o n - v o l a t i l e r e -  i n t h i s way i t was p a l e - y e l l o w and w e l l  b u t some p l a t i n u m m e t a l  coating of the t e t r a f l u o r i d e , 2.  u s i n g a low c o n c e n t r a t i o n o f e l e m e n t a l  always r e m a i n e d under a p r o t e c t i v e  w h i c h was i n v o l a t i l e  of the platinum  adduct  at t h i s  temperature.  tetrafluoride  (7)  P r e p a r a t i o n of the platinum t e t r a f l u o r i d e ,  bromine  trifluoride  adduct Platinum  tetrabromide  was d r i e d  b u l b o f a bromine t r i f l u o r i d e trifluoride to  overnight, at 70°, i n the s i l i c a  r e a c t i o n system.  occurred immediately  t h e bromine t r i f l u o r i d e  be m o d e r a t e d by c o o l i n g w i t h l i q u i d  oxygen.  e v o l v e d and a deep r e d s o l u t i o n was o b t a i n e d . f i f t e e n minutes,  Reaction with  Bromine was  and had  rapidly  and any bromine  were removed by vacuum d i s t i l l a t i o n a t room t e m p e r a t u r e . adduct  melted  T h i s was r e f l u x e d f o r  t h e n e x c e s s bromine t r i f l u o r i d e  t e t r a f l u o r i d e , bromine t r i f l u o r i d e  bromine  remaining  The p l a t i n u m  r e m a i n e d as a p a l e , r e d - b r o w n  solid. A n a l y s i s was by p y r o h y d r o l y s i s t o a t e m p e r a t u r e Founds  P t , 36.7;  F, 35.1.  Calc. for P t F  4  (BrFg)  of 300°. . P t , 35.9; F , 34.9$  33.  ( i i ) Thermal decomposition The platinum tetrafluoride, bromine t r i f l u o r i d e adduct was heated, under vacuum, i n a nickel boat contained i n an a l l glass-apparatus as shown i n Figure 5.  The temperature was held constant for six-hour  periods and was raised by intervals of 50°.  Decomposition started at  130° and bromine t r i f l u o r i d e collected i n the f i r s t trap.  A l l of the  bromine t r i f l u o r i d e was not removed u n t i l 300°, at which temperature the platinum tetrafluoride sublimed and started to decompose into platinum metal and fluorine.  To overcome this* a  sample of the adduct was  o heated, under vacuum, at 200  for twelve hours.  The platinum tetrafluoride  containing some residual bromine was then heated to 250° i n a stream of fluorine, when a l l the residual bromine was eliminated as a mixture of bromine t r i f l u o r i d e and bromine pentafluoride. Platinum tetrafluoride produced i n this manner was l i g h t brown, but x-ray powder photographs were poor, showing that the c r y s t a l l i t e s of the material were smaller than, the ideal for sharp-line photographs.  Analysis  was by pyrohydrolysis to a temperature of 300°. Found:  Pt, 71.7; F, 27.8; Bromine absent.  Calc. for PtF :- Pt, 72.0; 4  F, 28$. Properties Platinum tetrafluoride varies i n colour from pale yellow to brown. The higher the temperature of preparation, the paler the colour. It was not very hygroscopic and could be handled for short periods of time i n the atmosphere) without significant decomposition.  On pro-  longed exposure to moist a i r , however, hydrolysis occurred with the formation of the pale-yellow fluoroplatinic acid and a precipitate of hydrated  FIGURE 5  Apparatus used for studing decomposition reaction.  B19 Cone & socket  1 8  To vacuum system  34.  platinum dioxide. It reacted slowly with hydrochloric acid with the formation of chlorop l a t i n i c acid. The presence of fluoroplatinic acid and chloroplatinic acid i n these reactions were shown by examinations of their ultra-violet spectra.  The  spectrum of the fluoroplatinate ion i s not very pronounced, consisting of. two shallow peaks on the edge of a very strong charge-transfer band.  This species  was confirmed by converting i t to the deep-red hexaiodoplatinate (IV) ion by reaction with potassium iodide.  The reaction i s very slow i n sharp contrast  to the reaction of bromoplatinic acid and chloroplatinic acid with potassium iodide. The absorption peaks (m/f) for the halogenoplatinic acid are as follows.PtFg"  P t C 1 6  275,315  ~"  263  PtBr ~"(26) 6  305~  P t l 6  ~~  341,226  A magnetic moment study showed, the tetrafluoride to be diamagnetic. Infra-red  spectrum  The infra-red spectrum of the material i n a nujol mull was recorded! using both sodium chloride and caesium bromide optics.  A sharp peak at 675i cmi *  and a broad peak at 576 cm * were observed. The crystal structure of Platinum Tetrafluoride X-ray powder photographs of the material prepared by fluorination of platinum metal were interpreted on the basis of a pseudo-tetragonal unit c e l l , a = b =6.668 £ 0.005A\ C = 5.708; £ 0.005A\ ot* y3 90°, =  Z = 4, V =s 253.5A , Dc =7.10 g.cm , Dm =6.12 g.cm >3  3  3  92.02 *r0.05° , J  (the discrepancy between  the observed and calculated values i s attributed to the specimen not being perfectly c r y s t a l l i n e ) . Observed and calculated values for l / d ^ are given, i n Table I I I .  35.  TABLE I I I .  Calculated and observed x-ray d i f f r a c t i o n data for platinum tetrafluoride hkl  Calc.  Obs.  Ions.  101 200 211 211 112 112 220 220 202 301 103 321 321 312 312 400 213 213 411 411 420 420 303 402 004 332 332 422 431 323 204 501 422 431 413 224 413 521 224 521 512 314 512  0.0532 0.0899 0.1399 0.1463 0.1661 0.1693 0.1735 0.1863 0.2127 0.2331 0.2987 0.3134 0.3329 0.3429 0.3525 0.3598 0.3854 0.3918 0.4065 0.4193 0.4369 0.4625 0.4786 0.4826 0.4910 0.5131 0.5419 0.5697 0.5736 0.5781] 0.5809/ 0.5928 0.5953 0.6120 0.6520 0.6646]  0.0545 0.0922 0.1425 0.1483 0.1680 0.1705 0.1764 0.1887 0.2141 0.2356 0.3007 0.3170 0.3348 0.3456 0.3543 0.3630 0.3873 0.3932 0.4104 0.4205 0.4409 0.4639 0.4802  10 9 8 8 7 7 3 3 2 8 5 6 5 7 8 6 5 4 6 6 6 4 3  0.4913 0.5151 0.5420  3 4 6  0.6648 I 0.6668J 0.6784 0.6988] 0.6994 / 0.7111 0.7154  -  0.5800  -  -  — —  7 —  0.5953 0.6118 0.6529  55  0.6663  &  6 3  —  0.7004  7  -  -  0.7163  9  TABLE III cont'd  hkl  Calc.  Obs.  440 314 440 105 600 433 503 404 611 433 532 611 815 620 215 523 620 541 532 424 602 523 424 305 541  0.7164 0.7207 0.7675 0.7898 0 . 8095 0.8191 0.8383 0.8508 0.8530 0.8575 0.8633 0.8722 0.8765 0.8802? 0.8829J 0.9123 0.9186 0.9206 0.9213 0.9279 0.9323 0.9443 0.9535 0.9697 0.9846  —  -  0.8111 0.8216 0.8403 0.8504 0.8549 —  0.8654 0.8707 —  0.8806 0.9127  lob — — —  5 5 1 6 6  -  3 3 —  2 5  —  —  -  —  -  0.9278  4 -  0.9435 0.9504 0.9655 0.9819  3 3 1 4  37.  The following regularities i n reflections were noted, hkl present i f h + k + 1 = 2n hko present i f h  2n and k = 2n  Okl present i f k +• 1 » 2n hhl present i f 1 = 2n and 2h +- 1 = 4n these indicate that the l a t t i c e i s body-centred and 001, 150 and 110 are glide planes.  The regularities place the molecule i n a space group re-  lated to the tetragonal space group D ^-I4j/amd. 4  Reaction of platinum tetrafluoride (i)  With selenium tetrafluoride (16) A suspension of platinum tetrafluoride i n selenium tetrafluoride was  refluxed for f i f t e e n minutes at atmospheric pressure.  The platinum tetra-  fluoride p a r t i a l l y dissolved, with the formation of a pale, yellow-pink solution, which after removal of excess solvent under vacuum yielded a pale, yellow solid, which had a pink fluorescence. The material was analysed by f i r s t decomposing a known weight of material i n a 5$ sodium carbonate solution. give a pale-yellow solution.  I t dissolved completely to  Aliquots were taken;  selenium was estimated  by precipitation as the metal from a solution acidified with concentrated hydrochloric acid. determination.  Platinum was determined on the f i l t r a t e from this  Fluorine was estimated as lead chlorofluoride after a  Willard and Winter d i s t i l l a t i o n . Founds  Pt, 34.92;  Se, 27.2;  Se, 25.5;  F, 39.3$.  F, 36.5.  Calc. for P t F  4  (Se F ^ :  Pt, 33.5;  38.  ( i i ) With i o d i n e p e n t a f l u o r i d e Platinum the mixture  t e t r a f l u o r i d e d i d n o t d i s s o l v e i n i o d i n e p e n t a f l u o r i d e when  was r e f l u x e d  the s o l v e n t l e f t  and no a p p a r e n t  a light-brown s o l i d .  be p l a t i n u m t e t r a f l u o r i d e  Platinum  t e t r a f l u o r i d e was h e a t e d No a p p a r e n t  Chemical  tetrafluoride  i n a stream  of sulphur  With c h l o r i n e  lines  r e a c t i o n occurred u n t i l sublimed  a  tetrafluoride temperature  on t o t h e w a l l s o f t h e  a n a l y s i s o f t h e r e s i d u e showed i t t o be  platinum  and an x - r a y powder p h o t o g r a p h r e v e a l e d no l i n e s  those of platinum (iv)  showed t h i s t o  tetrafluoride.  3 0 0 ° , when p l a t i n u m t e t r a f l u o r i d e  apparatus.  analysis  tetrafluoride  i n a c l o s e d system. of  Chemical  Removal o f  and an x - r a y powder p h o t o g r a p h showed no  other than those of platinum ( i i i ) With sulphur  reaction occurred.  other  than  tetrafluoride. trifluoride  Chlorine t r i f l u o r i d e  d i d not i n t e r a c t with platinum  i n a c l o s e d s y s t e m , below 3 0 0 ° .  A t t h i s temperature,  tetrafluoride,  an orange  solid  condensed on t h e c o o l e r w a l l s beyond t h e h e a t e d  zone and a p a l e y e l l o w  solid  nitrogen.  collected  i n the traps cooled with l i q u i d  The orange  and y e l l o w m a t e r i a l s were shown by m e l t i n g p o i n t d e t e r m i n a t i o n (m. 170°) and  by x - r a y powder p h o t o g r a p h s t o be i d e n t i c a l w i t h t h e m a t e r i a l p r o -  duced by t h e r e a c t i o n o f c h l o r i n e t r i f l u o r i d e (v)  with  Pt0J? . 2 o o  W i t h powdered g l a s s A mixture  o f equal  q u a n t i t i e s of platinum t e t r a f l u o r i d e  g l a s s , p l a c e d i n a n i c k e l b o a t , was h e a t e d i n an a p p a r a t u s  similar  with l i q u i d nitrogen.  and powdered  i n an atmosphere o f n i t r o g e n  t o t h a t shown i n F i g u r e 5.  The t r a p s were c o o l e d  39.  The material was heated, for six hour periods, at a series of temperatures .and at 50° intervals, analysis.  samples were taken for x-ray powder  No apparent reaction occurred until a temperature of 350°  when s i l i c o n tetrafluoride condensed i n the f i r s t trap, and the x-ray powder photograph showed lines due to platinum metal.  Further heating  resulted i n the reduction of further platinum tetrafluoride to platinum metal with no intermediate fluoride produced. THE PLATINUM TETRAFLUORIDE, BROMINE TRIFLUORIDE ADDUCT, P t F ( B r F > 4  g  2  Preparation The bromine t r i f l u o r i d e adduct of platinum tetrafluoride was prepared as described under the preparation of platinum tetrafluoride. It was also prepared by the reaction of bromine t r i f l u o r i d e with PtO^Fg or platinum pentafluoride. Properties The adduct was found to be a pale, red-browm solid (m. 132° (sealed tube)).  The melt was deep-red and viscous and slowly attacked the glass  container.  The solid was rapidly hydrolysed and gave a clear orange  solution containing the fluoroplatinate ion.  An x-ray powder photograph  showed i t to be crystalline* but the pattern was somewhat complex and d i f fuse, and no attempt was made to index i t .  The solid was diamagnetic.  An attempt was made to displace the bromine t r i f l u o r i d e with iodine pentafluoride, but no replacement occurred even on prolonged refluxing. THE PLfflNUM TETRAFLUORIDE, SELENIUM TETRAFLUORIDE ADDUCT, PtF (SeF ) —"  •—~———————  4*  4 2 7  Preparation The platinum tetrafluoride, selenium tetrafluoride adduct was prepared  40.  as described under the reaction of platinum tetrafluoride.  I t was obtained  by the action of selenium tetrafluoride on PtO^Fg or platinum hexafluoride. Properties The adduct was found to be a palej yellow solid which did not melt, but decomposed on heating to 350° into platinum metal and selenium tetrafluoride.  It reacted exothermally with water to give a solution con-  taining the fluoroplatinate ion.  I t was found to be diamagnetic.  A sharp x-ray powder pattern was obtained.  This was almost identical  with the patterns previously obtained from the germanium (77) and palladiumanalogues (78, 79).  These photographs were indexed on the basis of hexag-  onal unit c e l l s containing four molecules:PtF (SeF ) 4  4  2  PdF (SeF ) 4  4  2  GeF^SeF^  a  15.74 t 0.01  15.47 t 0.01  15.60 ± 0.01  c  4.93 £ 0.01  4.88 ± 0.01  4.93 f 0.01  1015  1040  3.26  2.93  V Dc  1055 3.66  ;  X X  3  g.cm"  3  Observed and calculated values for l / d ^ are given i n Tables IV, V and VI. POTASSIUM FLU0R0PLATINATE (IV) Potassium fluoroplatinate (IV) was prepared by the method of Sharpe(7). The infra-red spectrum of a nujol mull of the material was recorded over the range 400—4000 cm *.  The following peaks were observed:-  488(m), 528(w), 538(w), 583(s), 730(m), 1050(v.s. broad), 1308(w) (32).  41.  TABLE IV.  Calculated and observed x-ray d i f f r a c t i o n data for PtF. ( S e F j 4 4 2 0  u i  hkl  Calc.  110 210 001 220 310 211 400 301 320 311 401 330 004 510 102 421 600 430 402 440 700 620 502 602 003  0.0166 0.0388 0.0415 0.0665 0.0720 0.0803 0.0886 0.0912 0.1053. 0.1135. 0.1309 0.1496 0.1660 0.17171 0.1715J 0.1966 0.1994 0.2050 0.2546 0.2659 0.2715 0.2880 0.3045 0.3651 0.3735S  Obs.  lobs.  0.0177 0.0388 0.0446 0.0680 0.0735 0.0805 0.0886 0.0926 0.1065 0.1127 0.1310 0.1516 0.1659 0.1700  10 8 10 9 9 6 4 5 3 9 5 9 5 6  0.1971 0.2016 0.2077 0.2552 0.2659 0.2717 0.2869 0.3027 0.3641 0.3733  3 3 2 4 8 3 7 6 5) 7  42.  TABLE V.  Calculated and observed x-ray diffractioni data for PdF, ( S e F ) 4 4  2  I/  hkl  Calc.  110 210 001 220 310 211 400 301 311 401 330 411 002 510 102 501 440 421 600 402 440 700 620 441 422 540 630 711 602 003  0.0167 0.0390 0.0419 0.0668 0.0724 0.0809 0.0891 0.0920 0.1143 0.1310 0.1504 0.1616 0.1676 0.17271 0.1732J 0.1812 0.1899 0.1979 0.2005 0.2576 0.2674 0.2729 0.2896, 0.3093 0.3236 0.3398 0.3509 0.3594 0.3681 0.3771  Obs. 0.0166 0.0388; 0.0441 0.0672 0.0731 0.0810 0.0892 0.0926 0.1138, 0.13353 0.1518 0.1597 0.1662 0.1718 0.1797 0.1866 0.1966 0.2023 0.2559 0.2675> 0.2764 0.2897 0.306,7 0.3221 0.3412 0.3513 0.3582 0.3679 0.3771  43,  TABLE VI.  Calculated and observed x-ray diffractiom data for GeF (SeF„) 4 4'2 n  bkl  Calc.  110 210 001 300 220 310 211 400 301 320 311 410 401 330 411 002 102 510 501 202 600 402 440 700 332 621 540 630 602  0.0165 0.0385 0.0419 0.04953 0.0660 0.0715 0.0795 0.0880 0.0905 0.1045; 0.1125 0.1155 0.1290 0.1485 0.15653 0.1640 0.1695\ 0.1705U 0.1785) 0.1860 0.1980 0.2520 0.2640 0.2695 0.3125 0.3270 0.3355 0.34653 0.3620  Obs. 0.0165 0.0389 0.0430 0.0497, 0.0675; 0.0730 0.0800 0,0864 0.0910 0.1050 0.1134 0.1168 0.1324 0.1501 0.1572 0.1637 0.1706 0.1782: 0.1859 0.1997 0.2540 0.2641 0.2725 0.3111 0.3264 0.3400 0.34963 0.3655,  44.  PENTAPOSITIVE PLATINUM PLATINUM PENTAFLUORIDE, PtFg. Preparation Platinum pentafluoride was prepared, at 350°, by the fluorinationi of platinum dichloride, contained i n a nickel boat, i n a s i l i c a apparatus. It collected as a deep-red solid just beyond the reaction zone.  When  fluorination was complete, the apparatus was sealed off at both ends of the  reaction tube.  10 mm.  The material was transferred, i n a dry-box, to a  s i l i c a tube tapering into a 5 mm.  s i l i c a tube.  The platinum penta-  fluoride was warmed, under vacuum, i n an attempt to melt i t into the narrower tube and at the same time sublime off any PtO^Fg that had been formed simultaneously with the pentafluoride.  Because of the high sur-  face tension and viscosity of the melt and the production, of s i l i c o n tetrafluoride by interaction with the container, i t was not possible to obtain a continuous column of the material i n the narrow tube.  Instead, several  bands were formed at different levels i n the tube. Analysis was carried out by decomposing a known weight of material in. a 5$ solution of sodium carbonate and determining the platinum, precipitated and i n solution, and the fluorine as previously described. Found:  Pt, 65.0;  F, 32.8.  PtF_ requires Pt, 67.2;  F, 32.8$.  o  It was also formed i n fluorination reactions involving platinum metal and other platinum compounds where the temperature of fluorination was greater thani350°, but the yields i n these instances were not as good as. with the fluorination of the dichloride. It was also formed by the photolysis of platinum hexafluoride.  45.  Properties The investigation of the properties of platinum pentafluoride was severely limited by i t s high surface tension and i t s ready disproportionationi into platinumi tetrafluoride and platinum hexafluoride. It was found to be a deep-red, glassy solid (m. 80°). was deep-red, had a very high surface tension and viscosity.  The melt, which The boiling  point could not be estimated because of i t s ready disproportionation. That t h i s disproportionation occurs even at the melting point was shown by the decrease i n melting point on subsequent determinations.  Disproportion-  ation was found to be very rapid at 200°, i n a vacuum, platinum: hexafluoride was condensed out i n a trap cooled with liquid nitrogem and the residue of platinum tetrafluoride was recognized by i t s x-ray powder photograph. A magnetic study, which was necessarily qualitative due to the irregular packing of the tube, showed i t to be paramagnetic. An x-ray powder photography taken of the material melted into a s i l i c a x-ray capillary, did not give a pattern of lines. Reactions of platinum pentafluoride (i)  With water It reacted exothermally with water, approximately  25$ of the platinum,  being precipitated as the hydrated dioxide, the remainder going into solution, as the fluoroplatinate ion. ( i i ) With bromine t r i f l u o r i d e It reacted with bromine t r i f l u o r i d e only on prolonged refluxing, to give a deep orange solution. crystals were obtained.  On removing the excess solvent, pale-orange  These were shown, by an x-ray powder photograph to  be the lj.2 platinum tetrafluoride, bromine t r i f l u o r i d e adduct described above.  46.  2.  With potassium bromide i n bromine t r i f l u o r i d e solution. Interaction with potassium fluoride i n bromine t r i f l u o r i d e was tried  in an attempt to prepare potassium fluoroplatinate (v).  Because the  platinum pentafluoride could not be weighed out accurately, an^ estimated excess was taken.  Reaction was more rapid than the reaction between!  bromine t r i f l u o r i d e and platinum pentafluoride alone. evolved and a deep red solution* remained. a pale-yellow solid.  Some bromine was  Removal of excess solvent:, l e f t  An x-ray powder photograph of this revealed only  lines due to potassium fluoroplatinate (IV) and the platinum tetrafluoride, bromine t r i f l u o r i d e adduct. 3.  With iodine pentafluoride. It reacted very slowly with iodine pentafluoride, dissolving on pro-  longed refluxing, with the formation of a cloudy red solution. of excess solvent, overnight, l e f t a pale orange s o l i d .  Removal  The product gave  an x-ray powder pattern identical with that obtained for the reaction between iodine pentafluoride and PtO F„. 4.  This material proved to be PtF_, IF .  With sulphur tetrafluoride. No reaction occurred between platinum pentafluoride and gaseous sulphur  tetrafluoride, even on, heating to the melting point of platinum pentafluoride. POTASSIUM FLUOROPLATINATE.(V), KPtFg Preparation 1.  Reaction of potassium fluoride with PtO_F„ i n iodine _ 2 o pentafluoride solution. Equimolar quantities of potassium fluoride (0.093g) and ^^O^Fg (o.534g)  were weighed i n a dry-box, into a s i l i c a bulb attached, by a graded; seal, to a breakseal.  The bulb was sealed under vacuum and joined to an iodine  47.  pentafluoride-reaction system. pentafluoride melted.  Reaction occurred immediately the iodine  There was a slow evolution of gas and a cloudy-  red solution was formed.  Some material (presumably the potassium fluoride,  which isnot very soluble i n iodine pentafluoride) did not react i n the cold. The solution was refluxed for f i f t e e n minutes.  On removal of the excess;  iodine pentafluoride at room temperature, a mustard-yellow, solid remained. Analysis was by pyrohydrolysis to 300°. Found: 2.  F, 32.0;  Residue, 69.0.  KPtF  g  requires F, 32.7; Pt, 56.0;  K,11.3$.  Fluorination of a mixture of platinum tetrachloride and potassium chloride. A finely-ground, equimolar mixture of platinum tetrachloride(0.47g.)  and potassium chloride (o.lg.) contained i n a nickel boat was heated i n a stream of fluorine.  The temperature was slowly raised, no reaction'. o  occurred u n t i l a temperature of 120 , when the material blackened i n patches, with apparent sintering.  The temperature was slowly raised to 300°, above  this temperature v o l a t i l e platinum fluorides were produced.  The residue  appeared heterogeneous, consisting of a mixture of black and yellow specks. An x-ray powder photograph showed that the material was a mixture of potassium fluoroplatinate (IV) and potassium fluoroplatinate (v). 3.  Subliming PtO^Fg on to potassium fluoride under vacuum. Potassium fluoride, contained i n a nickel boat, was heated to 70°.  PtOgFg was sublimed over this under vacuum.  A deep yellow residue re-  mained, this was shown by an x-ray powder photograph to contain mostly potassium fluoroplatinate (V) with smaller quantities of potassium! fluoroplatinate (IV) and unreacted potassium fluoride.  4'8.  Other, unsuccessful, attempts to prepare potassium hexafluoroplatinate (V) were made as follows:1)  Heating an equimolar mixture of potassium?fluoride and platinum d i -  chloride to 200° i n a stream of fluorine. 2)  Heating an equimolar mixture of potassium fluoride and PtO^Fg i n an  atmosphere of nitrogen. 3)  By the action of excess bromine t r i f l u o r i d e on an equimolar mixture  of platinum metal and potassiumi fluoride. 4)  By the action of excess bromine t r i f l u o r i d e on an equimolar mixture of  potassium fluoride and platinumi tetrachloride. Properties Potassium hexafluoroplatinate (V) i s a deep-yellow crystalline s o l i d . It could be stored indefinitely i n well-dried, sealed tubes. however, i t slowly decomposed, evolving ozone smelling gases.  In moist a i r , It reacted  exothermally with water evolving ozone smelling gases and giving a pale yellow precipitate, which was shown, by an x-rray powder photograph to be potassium fluoroplatinate (IV).  A magnetic study showed i t to be para-  magnetic ( Ms. 0.87 Bohr magnetons).  An infra-red spectrum, of a nujol  mull, recorded using both sodium! chloride and caesium bromide optics, showed a single broad absorption band that had peaks at 590 and 640 cm The Crystal Structure of potassiumi fluoroplatinate (v). X-ray powder photographs of potassium fluoroplatinate were interpreted on the basis of a rhombohedral unit c e l l , a - 4.87 ± 0.02 cx = 97.7 ± 0.2°;  V = 113  X. 3  Dc = 5.11 g.  X;  cm" . 3  Calculated and observed values for l/d are given i n Table VII.  49.  TABLE VII.  Calculated and observed x-ray d i f f r a c t i o n data for KPtF„  u i hkl  Calc.  Obs.  lobs.  100 101 110 111 200 201 211 211 202 211 212 301 310 302 312 312 311 321 322  0.0421 0.0714 0.0971 0.1134 0.1684 0.1847 0.2140 0.2397 0.2853 0.3170 0.3274 0.3824i 0.4597 0.4700 0.4992, 0.5250 0.5533 0.6023 0.6642  0.0421 0.0717 0.0974 0.1139 0.1691 0.1850 0.2150 0.2396 0.2867 0.3180 0.3288 0.3811 0.4591 0.4690 0.5000 0.5254 0.5521 0.6061 0.6639  10 10 8 7 6 3 5 9 4 2. 3 7 6 6 5, 4 1 2 3  50.  THE PLATINUM PENTAFLUORIBE, IODINE PENTAFLUORIBE ABDUCT, PtF ,lF_ 5 5 K  Preparation The platinum pentafluoride, iodine pentafluoride adduct was prepared as described under the reactions of platinum pentafluoride and PtO F„. 2 6 Properties It was found to be a pale-orange crystalline solid.  It reacted  vigorously with water, evolving acid gases and giving a solution containing the fluoroplatinate ion.  I t reacted vigorously with  concentrated  hydrochloric acid, giving a solution which was found to contain the chloroplatinate ion.  Vigorous reaction occurred with most organic  solvents, with the precipitation of platinum metal. with carbon tetrachloride.  No reaction occurred  I t melted, though not sharply, at about 140°  with attack on the glass container.  A decomposition study showed that:  the material started to decompose at about 180° and decomposition was complete at 300°, platinum tetrafluoride remained as the residue. A magnetic moment., study showed the material to be paramagnetic ( ^=0.65 Bohr magnetons).  An x-ray powder photograph showed that the  material was crystalline, but the patterm was complex and no attempt was made to index i t . THE PLATINUM PENTAFLUORIBE, CHLORINE TRIFLUORIDE ADDUCT, P t F C 1 F „ 5 3 Preparation l)  Fluorination of platinum dichloride In the fluorination of platinum dichloride to prepare platinumi penta-  fluoride, a platinum pentafluoride, chlorine t r i f l u o r i d e adduct condensed i n the traps of the fluorination apparatus as a pale-yellow powder and i n  51.  the zone after the platinum pentafluoride and before the traps as an iridescent film. 2)  Reaction of chlorine t r i f l u o r i d e with platinum tetrafluoride Chlorine t r i f l u o r i d e was passed, over platinum tetrafluoride, contained  in a nickel boat i n a closed system. zone was raised i n 50° intervals.  The temperature of the reaction  No reaction occunred until a tempera-  ture of 350° when the platinum pentafluoride, chlorine t r i f l u o r i d e adduct condensed as a l i g h t yellow solid i n the f i r s t trap, and as a light orange solid on the tube following the reaction zone. 3)  Reaction of chlorine t r i f l u o r i d e with Ptp Chlorine t r i f l u o r i d e was  F  g  condensed on to PtO^Fg i n a closed system.  A vigorous evolution of gas occurred on warming with the formation of a solution which was deep-red at f i r s t ;  as the reaction proceeded, the  colour became paler, and was f i n a l l y pale-orange.  The trap was them  cooled i n liquid oxygen.  The end trap of the system was  cooled i n liquid  nitrogen and sealed o f f .  The gas i n this end trap was analysed on the  mass spectrometer, oxygen difluoride, fluorine, oxygen, ozone and were sought.  Only oxygen, i n high concentration, was found.  nitrogen  The excess  chlorine t r i f l u o r i d e was d i s t i l l e d from the solutioni under vacuum and a deep red v o l a t i l e material transferred with i t . be chlorine monoxide.  The latter could possibly  The chlorine t r i f l u o r i d e adduct^ remained behind as  a pale-orange residue. Analysis was performed by pyrohydrolysis to 300°. (Found:  Pt, 51.9;  F, 39.7$,).  F, 38.4.  PtFgClFg requires Pt, 51.0;  C l , 9.3;  52.  Properties The platinum pentafluoride. chlorine t r i f l u o r i d e adduct varied i n colour from bright-yellow to orange depending on i t s mode of preparation. X-ray powder photographs showed i t to be well crystalline, but the pattern, obtained was complex and no attempt was made to index i t . sharply at 170-171° to a deep red l i q u i d .  I t melted  I t sublimed readily i n a good  vacuum at 100°, leaving an iridescent film on the cooler parts of the apparatus.  I t reacted vigorously with water with the evolution of pungent  gases and gave a pale yellow solution which contained the fluoroplatinate ion but not the chloroplatinate ion. PLATINUM OXYTRIFLUORIDE, Pt0F _______________________  o  y  Preparation Platinum oxytrifluoride was prepared by the fluorination of platinum dioxide at 200°. Analysis was by pyrohydrolysis to 500°. Found:  Pt, 73.1; F, 21.4.  Pt0F  g  requires Pt, 72.8; F, 21.3$.  It was also prepared, together with some platinum t r i f l u o r i d e , by the fluorination of platinum metal i n the presence of powdered glass. Properties Platinum t r i f l u o r i d e was found to be a light brown solid..  I t was,  stable to hydrolysis, and could be boiled with water without apparent, reaction.  X-ray powder photographs were sharp but complex, showing i t to be  well crystalline. tetrafluoride.  Samples were always contaminated with some platinum  53.  HEXAPOSITIVE PLATINUM PLATINUM HEXAFLUORIDE, PtFg Platinum hexafluoride was observed i n the fluorination of platinum metal at temperatures i n excess of 3 0 0 ° .  I t was best formed by fluorinating  o platinum metal i n i t i a l l y at 300 i n a very rapid stream of fluorine i n a nickel apparatus.  I t formed as deep-red (bromine-coloured) vapours directly  above the reaction zone, these i f swept away i n a rapid stream of gas could be condensed out as a deep-red (almost-black) solid. Reactions It was readily photolysed by v i s i b l e light, and gave a material which behaved as platinum pentafluoride. The hexafluoride hydrolysed very rapidly to give a black precipitate and a pale orange solution containing the fluoroplatinate ion. It reacted vigorously with selenium tetrafluoride to give a pale-yellow solid, which was shown by an x-ray powder photograph to be the platinum tetrafluoride, selenium tetrafluoride adduct. PtOgFg.  PLATINUM PEROXIDE HEXAFLU0RIDE(?)  Preparation 1.  PtOgFg was best prepared by the action of mixed fluorine and oxygeni o.  gases i n platinum metal at 450 . 6.  The apparatus used i s as showni i n Figure  The reaction chamber was made of thicfc-walled s i l i c a tubing,, which was  joined to the remainder of the apparatus through graded seals.  Many d i f -  ferent designs of traps, to maintain a turbulent gas flow through the apparatus were t r i e d . successful. nickel boat.  The arrangement  shown i n Figure 6 proved to be the most  The platinum sponge to be fluorinated was contained i n a  FIGURE 6  Apparatus used for preparation of P F ,N o^0 2  2  2  ,  o  A  _a CM  ro  -D  0)  j  i>  D D  t  0 ^  54.  The apparatus was evacuated and dried i n the usual manner, then.with traps 1 and 5 cooled with alcohol/solid carbon dioxide, oxygen, was admitted to the system through a sulphuric acid bubbler.  The remainder of the  traps were cooled with alcohol/solid carbon dioxide, then after f i r s t disconnecting the system from the vacuum l i n e , fluorine was passed, at a rapid rate over the platinum metal, i n i t i a l l y at room temperature. ture of the reaction zone was slowly raised.  The tempera-  Reaction f i r s t began at 350°  when a surface coating of platinum tetrafluoride was observed.  At 400°,  deep-red vapours of platinum hexafluoride were seen and simultaneously the  deep red platinum pentafluoride was deposited on the cooler walls of o  the  reaction.vessel beyond the heated, zone.  At 425-450 , PtO^Fg was  noticed as a deep red filmi beyond the reaction zone and as a fine paleorange powder i n the traps. as,  At this temperature, the s i l i c a reaction  chamber was fluorinated, /was evident by the etching which occurred and by the  condensation of s i l i c o n tetrafluoride by liquid oxygen, when this was  used as a coolant for the traps.  The fluorination was terminated when  the  platinum metal i n the boat had been consumed, or when the attack on.  the  s i l i c a tube had become extensive.  The apparatus was flushed with  oxygen u n t i l a test with a f i l t e r paper moistened with potassium iodide showed the emergent, gas to be free from fluorine (usually i t was necessary to flush for about one hour). off 2.  The apparatus was then evacuated and sealed  at points a, b, c, d and-e. The v o l a t i l e oxyfluoride was also prepared i n a similar manner to the  above with nitrogen replacing oxygen as the carrier gas.  This method  55.  however, gave a lower yield and gram quantities were obtained only after very extensive attack on the s i l i c a of the reaction tube. 3.  I t was also prepared with the platinum metal contained in. a nickel  reaction tube, which was attached to a train of traps by means of compression f i t t i n g s .  The v o l a t i l e oxyfluoride was produced wheni oxygeni  was used as the carrier gas but not with nitrogent as carrier gas.  Alter-  natively i t could be prepared when a mixture of platinum metal and platinum dioxide was fluorinated i n this manner even with nitrogen as carrier gas. The disadvantage with this method of preparation was that the glass tube leading into the nickel reaction tube rapidly became plugged.with product. 4.  I t was also produced when oxygen difluoride was passed oven heated  platinum metal i n a closed system. the  No reaction occurred u n t i l 350° when  platinum metal was attacked to produce a pale-yellow crust of platinum  tetrafluoride.  No further reaction occurred u n t i l 400°, when PtO. F con-  densed as a deep-red film beyond the reaction zone.  Because of the d i f -  f i c u l t i e s attendant i n the preparation of oxygen difluoride, this method i s not., of practical value. 5.  I t was produced i n low. yield by fluorinating other platinum compounds  in glass or s i l i c a apparatus. Purification It was purified by trap to trap d i s t i l l a t i o n ini the apparatus shown, i n Figure 7.  Three traps containing PtO^Fg were usually joined to a manifold  and the system beyond them dried under vacuum.  Trap 6 was cooled with  liquid oxygen and the break-seals on traps 1, 2 and 3 were broken.  Any  v o l a t i l e impurities were pumped off at room temperature, and these were collected i n trap 6.  Trap 4 was surrounded with liquid oxygen and traps  FIGURE 7  Apparatus used for purification of Pj. 02Fg  CNI  G: ~ r  O  -  C  LZJ  LO  33-  O  —*  .•-»  >  01  O oi O O  h-  CO 1  3  CO  56.  I, 2 and 3 were heated to 90 . trap 4.  The oxyfluoride sublimed from them into  When a l l the material v o l a t i l e at this temperature had sublimed,  the apparatus was sealed at a.  The coolant was removed from trap 4 which  was allowed to warm up to room temperature, any v o l a t i l e material being transferred to trap 6.  Trap 5 was surrounded with liquid oxygen and the  oxyfluoride was transferred to i t i n a similar manner. sealed at b and c.  The apparatus was  The PtO^Fg condensed on the cooler parts of the appara-  tus as a deep red solid.  I t was removed from the walls and powdered by  moving the nickel balls with a magnet.  I t was then shaken: into the tubes  x and y for magnetic moment studies, analyses etc. Analysis Analysis for both fluorine and platinum was effected by pyrohydrolysis* which proceeded very readily even at room temperature. (Found:  Pt, 57.5; F, 32.4.  p t 0  F 2  6  requires Pt, 57.2; F, 33.4$).  Platinum metal was determined separately by ignition of a known weight of material i n a platinum crucible i n an atmosphere of hydrogen: (Found:  Pt, 57.4$).  Fluorine was determined separately by fusion of the material with sodium i n a Parr bomb followed by precipitation as lead chlorofluoride (Found:  F, 32.7$).  triflunride.  Oxygen was determined by displacement with bromine  Found:  0, 10.4.  PtO„F requires 0, 9.4$. 2o c  Properties PtOgFg, depending on i t s state of division, existed either as a fine, orange-brown powder or as a deep red film.  On cooling, there was:  a reversable colour change from red-brown at about -120° to bright orange below this temperature.  I t sublimed readily i n a good vacuum at 90° and  57.  melted i n a sealed tube at 219 evolution of gas.  , to a deep-red, viscous liquid, with the  I t hydrolysed rapidly i n moist a i r , and so had to be  handled i n sealed systems and stored i n sealed, dry pyrex bulbs.  It,  could be stored indefinitely under these conditions. It reacted violently with most organic solvents, but not with carbon. tetrachloride, i n which i t did not dissolve. Crystal structure for PtO„F 2 Q-' c  The x-ray powder pattern was interpreted on the basis of a body-centred.' cubic unit c e l l containing eight molecules: a  a  10.032 ± 0.002 X;  V - 1009.6 X ;  Dc = 4.48  3  Observed and calculated values for l/d  g.cnf * ; Dm = 4.20 3  g.cm" . 3  are given i n Table VIII.  The observed indices of the reflection show the following relationship, hkl present only when h + k + 1 = 2n indicating that the l a t t i c e i s body centred.  A suitable space group  could not be found. The platinum atoms, which have a high scattering factor must be situated on a simple cubic l a t t i c e , a = 5.016  ± 0.001  X since a l l of the lines, with  the exception of four week ones, can be indexed on the basis of this  simple  58.  TABLE VIII.  Calculated and Observed x-ray d i f f r a c t i o n data for Pt0 F„ 2 6 n  1/d hkl 110 200 211 220 222 321 400 411 420 332 422 431 440 600, 442 620 622 444 640 642 800 820, 644 822, 660 662 840 842 664 844 10,0,0; 860 10,2,0; 862 10,2,2; 666 10,4,0; 864 10,4,2 880 10,4,4; 882 10,6,0; 866 10,6,2 12,0,0; 884 12,2,0 12,2,2;10,6,4 12,4,0 ,2; 10,8,0;886  Calc. 0.0199 0.0398 0.0597 0.0795 0.1193 0.1391 0.1590 0.1799 0.1988 0.2287 0.2385 0.25:84 0.3180 0.3578 0.3975 0.4372 0.4770 0.5167 0.55.64 0.6359 0.6757 0.7154 0.7552 0.7949 0.8347 0.8744 0.9539 0.9938 0.0340 1.0731 1.1526 1.1924* 1.2718, 1.3116 1.35:14 1.3911 1.4309 1.4706 1.5103 1.5898 1.6296  2  Obs. —  0.0413  -  0.0818 0.1217 0.1410 0.1614 0.1808 0.2020 0.2216 0.2415 0.2606 0.3209 0.3613 0.4010 0.4406 0.4800 0.5198 0.5600 0.6390 0.6787 0.7190 0.7582 0.7984 0.8381 0.8761 0.9558 0.&95:7 1.0361 1.0768 1.1549 1.1936 —  1.3134 1.3525 1.3925; 1.4313 1.4721 1,5118 1^5902 1.6300  lobs —  8  -  10 5 1 4 2 7 2 9 1 6 9 7 6 4 6 9 2 7 6 4 5 6 4 3. 4 7. 4 6 5  -4  4 4 3 2 5 3 6  &y.  Mass Spectrum A mass spectrum of PtO^Fg was recorded by subliming the material into a mass spectrometer.  The observed peaks and their assignments are given,  i n Table IX. TABLE IX. Mass  Mass spectrum of PtOgFg Assignment.  196  Pt*"  210 211 212  PtO  ? 227 2 2  229 230 231 2 4 2  243  r  +  PtO + 2 PtOF  +  PtO * 3  Species of greater mass number could not be detected on the mass spectrometers  available.  Infra-Red Spectrum The infra red spectrum was recorded using three different c e l l s s 1.  A stainless-steel-bodied c e l l with calcium fluoride windows.  The  spectrum was recorded both i n the vapour phase, with the c e l l heated to 100°, and with the material sublimed on to the c e l l windows. 2.  A glass-bodied c e l l with sodium chloride windows.  A spectrum of  material sublimed on to the windows was recorded. 3.  As i n 2, using potassium bromide windows. The observed absorption frequencies and their relative intensities  are given i n Table X.  60.  TABLE X.  Infra-red spectrum of PtfigFg (CM"  1  Intensity  )  631 680 725 975 1308 1448 1458 1495i 1505  v.s. w v.w. v.w. w m m m.w. m.w.  Ultra-violet and v i s i b l e spectrum The ultra-violet and v i s i b l e spectrum of PtO^Fg was recorded of^material that had been sublimed on to the quartz windows of a glass bodied c e l l . The absorption steadily increased with decrease i n wavelength, r i s i n g sharply at 4000 A* and showing a single maximum at 3500 X. Magnetic study A magnetic study was carnied out i n the range 88-300°K.  Values for  the molar susceptibilities i n this range are given, i n Table XI.  A plot  of l/'Ku versus temperature obeyed the Curie-Weiss law and gave a value of -6° for the Weiss constant.  The effective magnetic moment at 20° i s  2.45 Bohr magnetons. TABLE XI. T(°K) XM  Molar, susceptibilities of PtOgFg x 10 88 6066  116 4809  271 294 2498 2313  133 4290  146 175 4107 3670  204 3209  c.g.s. units  233 261 2801 2557  FIGURE 8  Apparatus used for measuring gas evolution  61.  Vapour-pressure  studies  A p r e l i m i n a r y vapour-pressure isoteniscope with nometer.  i n excess  of 1 5 0 ° ,  d i a p h r a m gauge has  man-  however, a t t a c k on t h e g l a s s  been d e s i g n e d  of  for this  s t u d y and  i t i s hoped  Pt0 F 2 o o  f t  W i t h water I t r e a c t e d v i o l e n t l y with water.  cipitate  and  w h i c h was  soluble  Oxygen was  a p a l e y e l l o w s o l u t i o n were o b t a i n e d .  v e r y f i n e l y d i v i d e d , was  some p l a t i n u m m e t a l  and  i n hydrochloric acid.  ( i ) i t s mass spectrum  shown, by x - r a y  evolved, a black: preThe  black  precipitate,  a n a l y s i s to c o n t a i n  i n a d d i t i o n some amorphous m a t e r i a l , which The  t a i n the f l u o r o p l a t i n a t e i o n . by  simple  s a t i s f a c t o r y measurements c a n be made i n t h e near f u t u r e .  Reactions 1)  out, u s i n g a  occurred.  A nickel that  carried  a l o w - v i s c o s i t y , f l u o r o l u b e o i l i n the d i f f e r e n t i a l  At temperatures  apparatus  s t u d y was  (ii)  pale yellow  T h a t t h e gas being absorbed  s o l u t i o n was  e v o l v e d was  found  t a i n i n g the f l u o r o p l a t i n a t e  ion.  con-  shown  by a l k a l i n e p y r o g a l l o l  (iii)  spectrum.  The o x y f l u o r i d e  a l s o r e a c t e d v i g o u r o u s l y w i t h water vapour t o g i v e an o r a n g e - y e l l o w p l a t i n u m d i o x i d e and  to  oxygen was  t h e absence o f a b s o r p t i o n bands i n i t s i n f r a - r e d  c i p i t a t e of hydrated  was  a golden yellow s o l u t i o n  T h i s r e a c t i o n w i t h water v a p o u r  preconwas  followed quantitatively,  t h e gas  volumes b e i n g measured u s i n g a TtJpler pump.  The  arrangement u s e d  similar  to t h a t used  and  i s shown d i a g r a m a t i c a l l y i n F i g u r e Bulb  tained  was  1 c o n t a i n e d water w h i c h had  a known w e i g h t o f PtO  F„.  by Emeleus and W o o l f ( 8 l )  8. p r e v i o u s l y been d e g a s s e d , b u l b 2  B o t h b u l b s had  con-  been s e a l e d under vacuum.  62.  Tap A lead to a high vacuum system and tap B to a Toplec pump. The apparatus was evacuated overnight through A. and the two break seals broken.  Tap A was closed  Water vapour soon reacted with the  material i n bulb 2, with the formation of hydrated platinum dioxide and fluoroplatinic  acid.  When a l l the material had reacted, both bulbs were  cooled i n liquid oxygen, and any gases pumped through B and their' volumes measured by the Topler pump.  Immediately the gas entered the pump, attack  of the mercury occurred with the formation of a black scum.  Analysis of  the gas, by mass spectrum, however, showed only oxygen: to be present.  A  further sample when opened under alkaline pyrogallol was almost completely absorbed. Results i)  0.8872 g or  ii)  1 gm. mole. 0.1908 g  or 2)  70.5) mis. oxygeni 27.1 1. 14.8 mis. oxygeni  1 gm. mole.  26.5 1.  With bromine t r i f l u o r i d e It reacted vigourously with bromine t r i f l u o r i d e , at room temperature,  in an open system to give a deep red solution.  On removal of the excess  bromine t r i f l u o r i d e under vacuum-, at room temperature,; a pale-orange compound remained.  This was shown, by x-ray analysis to be identical with  the platinum.tetrafluoride, bromine t r i f l u o r i d e adduct. The reaction was followed quantitatively i n a similar manner to the reaction with water.  In this case the bromine t r i f l u o r i d e was transferred  under vacuum to the PtO^Fg cooled with liquid oxygeni.  Any gases formed  63.  during the transfer, of bromine t r i f l u o r i d e were removed through A before allowing the materials to warm up and react.  The gas evolved again attacked  the mercury of the Tdpler pump* and again, was shown by mass spectrumi analysis and absorption i n alkaline pyrogallol to be oxygen. Results i)  0.1112 gor  ii)  1 gm. ml.  24.5: 1.  1  0.30493 g or  3)  8.0 mis. oxygeni  1 gm, ml.  22.5  mis.  25.1  1.  Wiith selenium tetrafluoride It reacted vigourously and with much effervescence with selenium; tetra-  fluoride>  at atmospheric pressure, to give a pale, yellow solution and a  deeper yellow s o l i d .  Evaporation of the selenium) tetrafluoride under-  vacuum, at room temperature,  l e f t a pale yellow s o l i d .  This was showni by  x-ray powder photographs to consist mainly of the platinum tetrafluoride,; selenium tetrafluoride adduct, there being i n addition, a faint pattern of another phase.  The gaseous products from this reaction, were collected for  infra-red and mass spectrometer  analysis*  The infra-red analysis showed the following peaks: 664 (w), 717 (w), 780 (v.s.), 842 (m) , 9253 (m), 1030 (v.s.), 1182 (w), 1286 (m.w.), 1438 ( s ) , 1484 (s) cm  A l l of which may be accounted for  by selenium hexafluoride (82) with the exception of the peak at 1030 cm * which can be accounted for as a silicon, tetrafluoride peak (83).  64.  A mass spectrum of the gas evolved showed only selenium hexafluoride and a small quantity of siliconi tetrafluoride to be present. Thus, i t was concluded that selenium hexafluoride and a small amount of s i l i c o n tetrafluoride were the maim gaseous products of this reactions. The reaction was again studied quantitatively using a Tttpler pump. Again, the mercury of the pump suffered attack by the gases evolved. Result 0.134 g. or 4)  18 mis. selenium hexafluoride  341 g.  45.8 1.  With Iodine pentafluoride It was reacted with iodine pentafluoride at atmospheric pressure.  The reaction, i n contrast to the reactions with selenium; tetrafluoride and with bromine t r i f l u o r i d e , was slow.  No reaction occurred at room  temperature, but on warming to about 35° a gas was slowly evolved and a deep-red solution formed.  As the reactiom proceeded, the solution be-  came paler and eventually a pale-orange solution remained.  Removal of  the excess iodine pentafluoride, under vacuum, at room temperature, l e f t an orange s o l i d .  This was shown to be a platinum pentafluoride, iodine  pentafluoride adduct. Analysis was by pyrohydrolysis to 250°. Found: 5)  Pt, 38.9; F, 34.2.  2 t F , 1F requires Pt, 38.1; F,37.1. g  5  With sulphur tetrafluoride It was reacted with sulphur tetrafluoride i n a closed system.  No  reaction occurred u n t i l 90°, when; the materials reacted i n the vapour phase to give a buff powder.  X-ray powder photographs of this material showed i t  65.  to be crystalline and to contain essentially one phase. Analysis, by pyrohydrolysis,showed  i t to contain 57.4$. platinumi  and 29.0$ fluorine. The experiment was repeated using a larger quantity- of PtO^Fg. Reaction occurred at a lower temperature, with great evolution of gas. An x^ray powder photograph of the residue showed i t to consist of a mixrture of the material obtained i n the earlier experiment, and platinumi tetrafluoride. 6)  For reactions with potassium fluoride and potassium fluoride in_  iodine pentafluoride solution, see under preparation of potassium fluoroplatinate (v). 7)  For reaction with chlorine t r i f l u o r i d e , see under the preparation,  of the platinum pentafluoride, iodine pentafluoride adduct.  66.  THE FLUORIDES OF RHODIUM RHODIUM TETRAFLUORIDE Preparation (7) a)  Preparation of a rhodium fluoride, bromine t r i f l u o r i d e adduct, RhF_,BrE„? Rhodium tribromide was dried at 110°, overnight, i n the bulb; of a  bromine trifluoride-reaction apparatus.  Reaction with bromine t r i f l u o r i d e  was slow at f i r s t , a greensolutioni being obtained.  On prolonged refluxrng,,  however, complete reaction occurred with the evolution of a large quantity of bromine and the formation of a deep red solution.  Excess bromine t r i -  fluoride was d i s t i l l e d off, under vacuum, over a period of 24 hours.  The  adduct remained as a pale-pink powder. No reaction occurred between.rhodium trichloride and bromine t r i fluoride under similar conditions. Properties of the adduct The adduct i s a pale-pink s o l i d .  An x-ray d i f f r a c t i o n photograph  showed a complex pattern of lines and no attempt was made to index t h i s . It was found to be diamagnetic.  I t reacted vigorously with water to  give f i r s t a deep-red solution and precipitate, then reacted further to give an olive-green solution and precipitate of hydrated rhodium dioxide. The bromine t r i f l u o r i d e adduct reacted vigorously with concentrated hydrochloric acid to give a pale-orange solution. b)  Decomposition of the adduct The adduct was heated i n a nickel boat i n the decomposition apparatus  (Figure 5). 50°,  I t began to evolve bromine t r i f l u o r i d e even on warming to  at the same time the material became amorphous.  However, a l l of the  67.  bromine t r i f l u o r i d e was not removed until a temperature of 300 .  At this  temperature an x-ray powder photograph indicated that the material was  o crystalline again.  On heating to 350  the x-ray patterm was sharper,,  though heating beyond this temperature did not improve the sharpness of further x-ray pictures. Analysis was carried out by pyrohydrolysis to 500?. Found:  Rh, 57.0;  F, 40.8.  Calc. for RhF^:  Rh, 57.5;  F, 42.5$.  Properties Rhodium tetrafluoride was a deep-violet solid.  I t was moderately  stable i n moist a i r and could be handled for short periods of time in, the atmosphere, without hydrolysis occurring.  That i s was f a i r l y stable to-  wards moisture was also shown by the fact that a temperature of 500° had to be reached before pyrohydrolysis was complete.  I t reacted with water,  to give an olive-green solution and precipitate. The infra-red spectrum, of a nujol mull of the material, was recorded using both sodium chloride and caesium bromide optics.  It showed a single  very broad peak extending over the range 576-678 cm Crystal structure for rhodium tetrafluoride X-ray powder photographs of rhodium tetrafluoride were indexed on,thebasis of a face-centred cubic c e l l containing sixteen molecules: a -» 10.292 £ 0.0021; V - 1090 A*; Dc = 4.37 g. cm" ; 3  3  Dm - 3.60 g.  cm" . 3  Calculated and observed values for l/d. are given i n Table XII. The observed indices of the reflections show the following relation*ship: hkl present only when h, k, 1 a l l even or;,.all odd which indicates that the l a t t i c e i s face-centred. These extinctions are compatable with either of the space groups F23 or F43m.  68.  TABLE XII.  Calculated and observed x-ray d i f f r a c t i o n data for RhF„ 1/d  hkl  Calc.  Obs.  lobs.  111 220 311 222 400 311 422:  0.0283 0.0755 0.1038 0.1133 0.1510 0.1794 0.2266 0.2549 0.3021 0.33041 0.4059J 0.4154 0.4531 0.4814 0.5&7.0 0.6042 0.6419 0.6797 0.7080 0.7552 0.7835; 0.8118 0.8590 0.9062 0.9346 1.0195 1.0856. 1.1611 1.20831 1.2366: 1.3216 1.5104 1.6237 1.6614  0.0287 0.0793 0.1051 0.1142. 0.1538 0.1809. 0.22853 0.2568 0.3038 0.3319 0.4068 0.4176 0.4547 0.4837 0.5591 0.6077, 0.6396; 0.6826 0.7171 0.75653 0.7868. 0.8125= 0.8610 0.9076. 0.935.5; 1.0205> 1.0871 1.1600 1.2096 1.2377 1.3223 1.5112 1.6290 1.6593  10 3 8 9 5 4 3 7 8, 8 5 8 5. 7 8 4 3 4 5: 6. 6. 4 5 6 5 6 5 4 3 5 8 3 4 3  511f  333 440 531 533 622 444 7115 551 7315 553 800 x  820 5 644't  822; 751;  2  660 555 840 911; 753 921; 761; 655$ 931 844: 933; 771; 755 1 0 , 2 , 2 ; 666. 955 1 1 , 1 , 1 ; 755S 880 1 , 3 , 1 ; 9 7 1 ; 955; 10,6,2 12,4,0 10,6,6 12,4,4  69.  Reaction of rhodium tetrafluoride with sulphur tetrafluoride Rhodium tetrafluoride was reacted with sulphur tetrafluoride i n a closed system.  No reaction occurred even on taking the temperature to  350°. PENTAPOSITIVE RHODIUM RHODIUM PENTAFLUORIDE? Preparation 1.  Fluorination of rhodium tetrafluoride Rhodium tetrafluoride was heated i n a stream of fluorine i n an attempt  to obtains a more crystalline sample.  No reaction occurred until a temera-  ture of 260°, when a deep-brown.vapour was noticed above the heated material and a pale-red film condensed on the cooler walls of the apparatus.  This  material on warming with a non-luminous flame tended to ball together ini a similar manner to platinum pentafluoride.  The rhodium tetrafluoride re-  maining i n the boat was found to s t i l l be amorphous. 2.  Fluorination of rhodium metal Rhodium metal contained i n a nickel boat, was fluorinated i n a silica<  reaction tube.  No reaction was observed;, u n t i l 375;° when; deep red vapours  were observed! above the heated metal.  Almost simultaneously an orange film,,  deep red i n bulk.began to form on the cooler parts of the apparatus. material behaved i n a similar manner to that, produced i r u l . the  s i l i c a apparatus very readily;  stopped.  This  I t attacked  because of this, the reaction was  The violet, residue remaining i n the boat was showni by x-ray  analysis to be a mixture of rhodiumi metal and rhodium t r i f l u o r i d e . In a subsequent experiment a trap cooled with liquid oxygen, was arranged! so that i t was very close to the reactiont zone, but no compound, v o l a t i l e  70.  at room temperature} similar to platinum hexafluoride was observed. On no occasion was sufficient v o l a t i l e material obtained for analysis.. Properties The material exists as a pale-orange film, (nwvyO ) which i s deep red 0  i n bulk.  It has a high surface tension as shown by i t s tendency to " b a l l " .  It reacted very vigorously with water to give a deep-blue precipitate and solution and evolved acid gases.  With concentrated hydrochloric acid  a blue-violet precipitate was obtained, this turned green, on standing. POTASSIUM FLU0RORH0DATE (V) An attempt was made to prepare this material by the reaction between, equimolar quantities of potassium bromide (o#348 g.) and rhodium tribromide ( l g) i n bromine t r i f l u o r i d e solution.  The reaction occurred with much  more vigour than the reaction between bromine t r i f l u o r i d e and rhodium) t r i bromide alone, giving a deep red solution.  Excess bromine t r i f l u o r i d e was.  d i s t i l l e d off, under vacuum, overnight, leaving a pale-pink solid.  An x-ray  powder photograph of this material indicated that there were two phases present.  One was identified as potassiumi fluororhodate (IV), the other  could not be identified.  71.  THE FLUORIDES OF PALLADIUM FLUORINATION. OF PALLADIUM METAL A rapid stream of fluorine was passed over palladium metal sponge, contained i n a nickel boat, i n a s i l i c a reaction tube. was slowly raised;  The temperature  no reactioni occurred until 150°, when the metal i n -  candesced and sintered to give a black residue which contained some l i g h t brown patches.  The temperature was slowly raised to a maximum of 500°,  but no furthen reaction occurred. -  An x-ray powder photograph showed that the material was principally palladium t r i f l u o r i d e with a trace of palladium difluoride. FLUORINATION OF PALLADIUM DIBROMIDE A rapid stream of fluorine was passed over palladium dibromide, contained i n a nickel boat, i n a s i l i c a reaction tube.  Reaction occurred  at room temperature, when a glowing zone passed down the boat, leaving a black: homogeneous residue.  A pale-yellow solid, presumably a mixture of  bromine t r i f l u o r i d e and bromine pentafluoride, condensed i n a trap cooled with an alcohol/solid carbon dioxide mixture situated after the reaction zone.  The temperature was then slowly raised to a maximum of 500° but no  further reaction occurred. An x-ray powder photograph of the residue showed only lines attributable to palladium t r i f l u o r i d e .  72.  TIN TETRAFLUORIDE, SnF  4  Preparation (84) Tin metal, contained i n a nickel boat, was heated to just above i t s melting point i n a stream of fluorine.  Tin tetrafluoride formed as a  white powder which was not v o l a t i l e i n the fluorine stream at this temperature. Analysis was by pyrohydrolysis at 350°.  Fluorine was estimated both  by titration- against standard alkali' and by precipitation as lead chlorofluoride.  Tin was estimated by heating the residue from pyrohydrolysis  i n a stream of a i r and weighing to constant weight as stannic oxide. Eound:  Sn, 61.10;  F, 36,65.  Calc. for SnF : 4  Sn, 60.97;  F, 39.03$.  Properties The i n f r a red-spectrum, of a nujol mull of the material, was recorded using both sodium chloride and caesium bromide optics.  A single, very/  broad, absorption band, extending over the range 575-694 cm * was observed. The crystal structure of t i n tetrafluoride The x-ray powder pattern of t i n tetrafluoride has been interpreted om the basis of a tetragonal unit c e l l containing eight molecules, a  a  8.773 £ 0.005X,  c = 7.187 ± 0.005X,  V  554A* , Dc = 4.66 g. 3  =  cm" , 3  —3 Dm = 4.68 g. cm  .  Calculated and observed values for l / d are given, i n Table XIII. 2  The observed indices of the reflections show the following relationship: 001 present only when  1  2n  hhl present only when  h - 2n.  These indicate the presence of two screw axes. group could not be found.  A suitable space  73.  TABLE XIII.  Calculated and observed x-ray diffraction; data for SnF„ 2  hkl 210 002 220 112 221 321 103 302 312 322 420 004 332 1104 430, 500 520 531 442 433, 503 611 523 541 424 305 315 640 006 306 651 326 660 830 117 506 813 840 900 922, 762 931 646 546  Calc. 0.0651 0.0776 0.1041^ 0.1026J 0.1235 0.18861 0.1875 J 0.1947 0.2077 0.2468, 0.2603 0.3102.1 0.3120 J 0.3232 "1 0.325.4 J 0.3774 0.4619 0.4941 0.4999"! 0.5010J 0.5519T 0.5530 ) 0.5705> 0.6019 0.6151 0.6768 0.6980 0.81511 0.8133J 0.8672 0.9371 0.9501 0.9761 1.0234] 1.0205J 1.0412 1.0542 1.1839 1.1918 1.2186 1.23i6  Obs.  lobs.  0.0655i 0.0789  7 10  0.1032  1  0.1247  7  0.1892  3  0.1942 0.2069 0.2476 0.2577  1 9 9 7  0.311  5>  0.3246.  9  0.3796 0.4615 0.4913  7. 6 4  0.5025,  6  0.5552  4  0.5682 0.5988 0.6134 0.6763 0.6952  4 1 4 4 3  0.8117  4  0.8676 0.9376 0.9492 0.9787  3 3 1 2  1.0207  1  1.04193 1.0560 1.1834 1.1931 1.2221 1.2325  1 4 4 2 4 2  TABLE XIII cont'd:.  hkl 940 517 527 844 772 10,3,1 943 10,0,3 10,4,0 961 816; 915. 11,0,0 944 11,1*0 707 10,4,2 119 10,3,3 10,5,0 11,0,2 880  Calc.  Obs.  lobs.  1.2625; 1.2885 1.3275) 1.3514") 1.3531J 1.4380*1 1.4370J 1.4760 1.5097 1.5422"! 1.5.440 / 1.5520 1.5748T 1.5729J 1.567&S 1.5878 J 1.5873J 1.5966i) 1.5931J 1.6269 1.6524 1.6659  1.2623 1.2848 1.3290  2  1.3494  2  1.4355;  7  1.4748 1.5057  8; 6i  1.5411  &  1.548&  4  1.5719  6j  1.5864  5  1.592.7,  3  1.6270 1.6497 1.6680  5 5. 7  7&. LEAD TETRAFLUORIBE Preparation (i)  Preparation of lead difluoride (85) Lead difluoride was prepared as a white powder by repeatedly evaporati  lead acetate with aqueous hydrofluoric acid under a n i infra-red lamp. ( i i ) Preparation of lead tetrafluoride (85) Lead difluoride, contained i n a nickel boat was fluorinated i n a s i l i c o tube.  No reaction occurred until 300 , when, the material became deep  yellow, and on further reaction became white once more.  No v o l a t i l e  products were observed. Analysis was by pyrohydrolysis at 150°, lead being estimated as; lead dioxide. Founds Pb, 73.8;  E, 26.0.  Calc. for PbF $ 4  Pb, 73.2;  F, 26.8$.  Properties Lead tetrafluoride i s a white powder, which hydrolyses rapidly i n moist a i r to give lead dioxide. A very complex x-ray powder pattern was obtained; and no attempt, was made to index i t .  I t i s probable that the crystal l a t t i c e i s of low sym-  metry or the unit c e l l large.  The pattern showed: some similarity to the  hafnium tetrafluoride pattern. An infra-red spectrumi recorded i n the sodium chloride and caesium bromide regions showed a strong peak at 525: cm * and a weaker peak at 640 cm" . 1  DISCUSSION  76.  THE VALENCY STATES OF PLATINUM Platinum, as with other transitiom metals, i s capable of existing in. a wide range of oxidatiom states.  In common with most of the elements,  the highest oxidation states occur i n the fluorides and oxides.  The  energy required to excifee any oxidation state must be offset by the energy gained im bond formation and, i f the compound i s a solid, the energy l i b e r ated i n forming a crystal l a t t i c e . The l a t t i c e energy of am ionic; compound i s directly proportional to the square of the anionic charge and inversely proportional to the interionic distance, which for* a given oxidation state of the cation depends on the ionic radius of the anion.  Now,  anionic r a d i i are at a minimum with  fluorine (r = 1.36A*) (86) and we would therefore expect fluorides to have higher l a t t i c e energies tham compounds of any other monovalent, ligand. The only ion of comparable size i s the 0^  (r •= 1.4oX)(86) ion;  because  of i t s double cha rge, this gives rise to, compounds having even greater l a t t i c e energies tham the corresponding fluorides. The energy required to dissociate a fluorine molecule into fluorine atoms i s low (AH  = 38 k. cals) (87) whereas the dissociation of an oxygeni  molecule into atoms requires three times this energy ( (88).  H =. 118 k. cals)  The formation of a bond to a fluorine atom therefore liberates much,  more energy than the combination with am oxygeni atom.  This difference  offsets the more favourable l a t t i c e energy in. the oxides.  These are the  factors which cause the elements to exhibit their highest oxidatiom states whem coordinated by oxygem or fluorine atoms. almost equally effective i n this respect.  Oxygen and fluorine are  77. The oxidation state may, of the central atom.  however,; be limited by the allowed coordination  Oxygen, because of i t s double charge, i s capable of  bringing out the same oxidation state with half the coordination which fluorine demands.  This may  well be the reason why  an octafluoride of  osmium has not been found, although osmium attains an oxidation state of + 8 i n osmium tetroxide and osmium trioxydifluoride (43). Although fluorine i s capable of exciting the high oxidation states, this does not exclude the p o s s i b i l i t y of preparing fluorides i n whichlower oxidation states exist. of a higher fluoride may  However, a very high enthalpy of formation',  i n some cases favour the disproportionation, of a  lower fluoride into the metal and a high, fluoride.  Waddington (89) has.  shown:, from thermodynamical considerations, that cuprous fluoride would: have a low enthalpy of formation and would be unstable towards dispropontionatiion to the difluoride and copper metal. Returning to platinum, a platinum atom i n i t s ground state has the electronic configurationi 5  6  s  p  d  4  B  2  6  9  -  1  and would i n theory be capable of attaining a maximum oxidation state of ten.  In practice, however, this has not been obtained, but as we would  expect the highest oxidation, obtained has been with fluorine and oxygen. At the onset of this work, the highest oxidation state of platinum  was  six, which existed i n both the poorly-characterized, trioxide and the:';: unstable hexafluoride. state was  Of the lower oxidation states, the tetrapositive  established i n platinum, tetrafluoride, but a t r i f l u o r i d e  was  78.  unknowns and a difluoride was reported but unconfirmed.  However, these  oxidation states were known for a variety of other ligands. positive state was unknown at that time*  The penta-  79.  PLATINUM DIFLUORIDE In the platinum group of metals, the only known difluoride i s that of palladium, though difluorides are known for most of the elements of the f i r s t transition series.  I t was thought, that by virtue of i t s similar  atomic size and electronic configuration*platinum; might resemble palladium! i n this respect. The structures of the known transition metaL difluorides f a l l into two groups (90), those c r y s t a l l i z i n g with a  r u t i l e , or distorted r u t i l e  l a t t i c e (chromium, manganese, iron, cobalt, nickel, copper,: i n c and palladium!) z  and those c r y s t a l l i z i n g with the f l u o r i t e arrangement (cadmium and mercury). By analogy, then, we would expect platinum difluoride to c r y s t a l l i n e with a r u t i l e or possibly a f l u o r i t e l a t t i c e .  The octahedral coordination which.  the platinum atom would have i n a r u t i l e l a t t i c e would only be 6  2  with the electronic configuration: d^ dl^, (90).  compatable  with the d^  electrons unpaired  A pairing of these electrons would lead to distortion of the octa-  hedron, such as i s found i n the dichlorides of platinum and palladiumi (91), where i n f i n i t e chains of planar MCl^ groups share chlorine atoms. palladium difluoride i s the only paramagnetic Pd palladium monoxide being diamagnetic;  2+  Now,  compound known, even 2+  thus we see the paramagnetic Pd  ioni i s not a very stable species and i t may well prove to; be impossible to stabilize the platinum! analogue. isoelectronic Au  I t should also be mentioned that the  ion i s diamagnetic i n potassium fluoroaurate and i t has  beem suggested (92) that the AuE  4  ion has a square planar- shape.  Although  auric t r i f l u o r i d e i s paramagnetic, i t i s not isomorphous with palladium t r i f l u o r i d e , as would be expected i f the gold atom had a regular octahedral coordination of fluorine atoms.  80.  Morris (93) , using a simple Born-Lande' expression, calculated l a t t i c e energies of the them known difluorides using interatomic distances.  the  crystallographic  The values he obtained compared favourably  with those obtained practically from the Born^-Haber cycle. Making similar calculations for the difluorides of platinum and palladium, assuming platinum difluoride to be isostructural with palladium; difluoride,gives values of 643 and 634 K cals per mole respectively for the l a t t i c e energies and corresponding values of 18 and 32 K cals per mole for the heat of formation of the compounds from their  elements.  Palladium difluoride has been prepared and well characterized (38, 39). The various attempts i n this work to prepare platinum difluoride have a l l been; unsuccessful.  Other workers have attempted, unsuccessfully, to  reduce platinum tetrafluoride by different methods.  Moissan; (2) tried to  obtain the difluoride from; the phosphorus t r i f l u o r i d e complexes with platinum: tetrafluoride, but was unsuccessful.  Bartlett (16) attempted to reduce  platinum tetrafluoride by similar means to those used for the reduction; of palladium t r i f l u o r i d e .  With sulphur tetrafluoride, he obtained a rust-  coloured solid, which was shown; to contain platinum metal together with a :  phase which was not identified, but which; did not have a r u t i l e structure. The selenium tetrafluoride adduct PtF^SeE^Jg showed no signs of decomposition, on heating, u n t i l 350° when i t decomposed rapidly into platinum' metal and selenium: hexafluoride.  Robinson; and Hair (76) also attempted  platinum tetrafluoride using selenium: tetrafluoride. isolated the compound PtE (seF.)  to reduce  They claim to have  which decomposed on heating (no temperature  was quoted) to give platinum metal.  I t would appear that their compound  which was incorrectly formulated (94), was the same as that reported by  81.  Bartlett and i n this work.Sharp (95) heated platinum tetrafluoride with carbon monoxide under pressure and obtained a mixture of the v o l a t i l e platinum dicarbonyl octafluoride and platinum metal. Although platinum difluoride, i s thermodynamically  possible when coit-  sidered to have a r u t i l e l a t t i c e , i t could prefer another l a t t i c e . However, a l l attempts to prepare i t have f a i l e d , a possible explanation! for this i s that i t i s unstable towards disproportionation. into platinum tetrafluoride and platinum metal. 2PtF -2 rt  As no thermochemical  *PtE;, + 4  Pt  data i s at present available for platinum tetra-  fluoride, i t i s not possible to confirm or reject this p o s s i b i l i t y .  82.  PLATINUM TRIFLUORIDE As shown i n Table I, trifluorides are known for a l l members of the platinum group except platinum and osmium.  For palladium and rhodium,  they may be prepared by the fluorination of the respective metal with elemental fluorine.  For iridium and ruthenium, they are best prepared  by reduction of the higher fluorides. Now,  structurally the t r i f l u o r i d e s of the transition metals may be  divided into three main groups:1)  Those having the rhenium trioxide l a t t i c e , this i s adopted by the  t r i f l u o r i d e s of niobium, tantalum and molybdenum. 2)  Those having the palladium t r i f l u o r i d e structure, this i s adopted  by the trifluorides of palladium, rhodium and iridium. 3)  Those having the vanadium t r i f l u o r i d e l a t t i c e , this i s adopted by  the t r i f l u o r i d e s of vanadium, iron, cobalt and ruthenium. Jack et al (96) i n their investigations of the t r i f l u o r i d e s of types 2 and 3 have shown the fluorides of group 2 to be hexagonal close packed arrangements of fluorine atoms with the metal atoms i n octahedral hole sites, and those of group 3 to be intermediate between these and the more open structure of rhenium trioxide type. It was supposed that i f a t r i f l u o r i d e of platinum did exist, i t would crystallize i n a l a t t i c e of either group 2 or group 3.  A l a t t i c e of this  type was found i n residues from the fluorination of platinum metal i n the presence of powdered glass (see plate 1) the compound could not, however, be isolated.  This l a t t i c e was indexed on the basis of a bimolecular  rhonbohedral unit c e l l , the dimensions of which are compared with those  PLATE 1. 1.PdF 2.Residues 3.PtOF 3  3  83.  obtained by Jack et al (95) for the trifluorides of the other Group VIII metals, i n Table XIV. TABLE XIV.  Unit-cell dimensions of the trifluorides; of Group VIII  •0) FeF  3  5J.362  57.99  CoF  3  5.279  56.97  RuF  3  5.408  54.67  EhF  3  5.330  54.42  PdF  3  5.5234:  53.925.  5,. 418  54.13  3 PtF I r F  3  5.41  .54.'3  84.  PLATINUM TETRAFLUORIDE Platinum tetrafluoride i s the easiest platinum fluoride to prepare and i s the most stable thermally.  I t does, however, decompose on heating above  350° to give the metal, no intermediate lower fluorides have been observed in this thermal decomposition.  This behaviour contrasts with the pyrolysis  of the corresponding tetrachloride and tetrabromide (97, 98);  ptm  — 4  PtBr,  3 9 0  °  ocn°  -Ptci —  4 4 0  Q  3 - PtBn_  4  4 9 0 °  —  —  ° - Ptci  5  9  0  °  -PtCl  -Pt  -PtBr  -Pft.  2 - PtBr  3  n  2  If platinum tetrafluoride i s heated i n a stream of fluorine, then oxidation occurs with the formation of a mixture of the penta- and hexafluoride. Nyholm and Sharpe (17) have reported platinum tetrafluoride to be paramagnetic (yU'» Now,  1.1 Bohr magnetons).  quadripositive platinum i s a d  Q  system; 6^  octahedrally coordinated, there would be a d^, quent, diamagnetism.  i f the platinum were  configuration and a conse-  The paramagnetism of Nyholm and Sharpe therefore sug-  gested a coordination number different from s i x .  Both the bromine t r i -  fluoride and selenium tetrafluoride \adducts of platinum tetrafluoride, were investigated and found to be diamagnetic.  Nyholm and Sharpe (17) had found  potassium fluoroplatinate (IV), i n which the platinum atom i s octahedrally coordinated by fluorine atoms, to be diamagnetic.  Accordingly, the magnetic  properties of platinum tetrafluoride were reinvestigated.  The fluoride as  prepared by the thermal decomposition of the bromine t r i f l u o r i d e adduct, (which was the method used by Sharpe and Nyholm i n preparing theiir- sample  Unit cell and bonding about one platinum in PtF^ Shaded fluorine a t o m s r e p r e s e n t the inner coordination sph<  85. for magnetic moment determination) was found to contain some bromine, probably combined as bromine t r i f l u o r i d e . the solid i n a stream of fluorine gas.  This was removed by heating A sample, prepared i n this manner,  giving a good analysis and x-ray pattern which was completely indexed, was found to be diamagnetic.  I t must therefore be supposed that the para-  magnetism of the compound of Sharpe and Nyholm was due to a paramagnetic impurity, i n a l l probability a bromine t r i f l u o r i d e adduct. The uncomplicated x-ray powder pattern was indexed on the basis of a body-centred monoclinic unit c e l l which i s closely related to the tetragonal 19 unit c e l l with space group  - I4/amd.  This i s the space group which  Mooney (99) had assigned to the tetrachlorides of uranium and thorium. The relative intensities of the lines of the platinic: tetrafluoride pattern show a close resemblance to those of the uranium tetrachloride and thorium' tetrachloride patterns, though i t must be emphasized that the monpclinic distortion only allows comparison to be made for the low angle lines.  There  is l i t t l e doubt, however, that the structure adopted by platinum.tetrafluoride i s very similar to that of uraniumi tetrachloride. Mooney  (99) interpreted the structure of uranium tetrachloride and  thorium tetrachloride on the basis of eight coordination, of the metal atom by the chlorine atoms. tetrahedra  }  metal atom.  The chlorine atoms are i n two sets of flattened  one set being at 2.46A* and the other set at 3.11A* from the Each chlorine i n the closely coordinated set i s one of the  more distantly coordinated tetrahedron on another platinum atom and vice versa.  In this way, each uranium or thorium atom i s coordinated to, eight  other metal atoms v i a the chlorine atoms.  I t would be expected that the  long chlorine-metal bonds could be easily brokeni with the separation of  86,  discrete uranium tetrachloride and thorium tetrachloride molecules. Both uranium tetrachloride and thorium tetrachloride can be sublimed and Mooney (99) pointed to this being consistant with the structure. That this structure i s the one found i n platinum tetrafluoride i s also supported by the ready sublimati on of this material above 300°. A f u l l structure determination! was not attempted for platinum;tetrafluoride, because of the d i f f i c u l t y of locating the very light fluorine atoms i n the presence of the very heavy platinum atoms.  However, assuming  the coordination of platinum atoms by fluorine atoms was similar to the coordination of thorium and uranium; atoms by chlorine atoms, bond lengths were calculated and found to be 1.90A* for the short bonds and 2.14% long bonds.  for the  The short-bond length of 1. 90X compares very favourably with  the value of 1.91A* for the Pt(lV)-F bond found by Mellor and Stephenson.(32) i n potassium fluoroplatinate (IV).  87  PLATINUM PENTAFLUORIDE TABLE XV.  Known pentafluorides of the second and third transition series  NbF (100) s  m. b.  ~80°" 235°  MoF (101)  /  fi  ~67°" 273.6  RhF ?^ g  107°" 313°  TaFg (100) m. b.  RuF . (46>)  &  ReF (103) 5  95° 229°  48° 221.3  J  OsF (103) &  70° 225.9°  IrF  4  (45)  106° 300°  FtFg/ 80«  this work.  Table XV l i s t s the pentafluoride of the second and third; transition.series together with their melting and boiling points.  Of. the platinum group, the  pentafluoride of ruthenium has been established since 1925 (36).  The penta-  fluoride of osmium has been, known since 1912 (40), but i t was only recently (104) that i t was characterized as such.  Iridium tetrafluoride has been, tentatively  c l a s s i f i e d here with the pentafluorides, because i t s properties and mode of preparation j u s t i f y the suspicion that i t i s a pentafluoride (103).  I t cant  be seen that the pentafluoride of platinum: and the, as yet poorly characterized, pentafluoride of rhodium f i t into this scheme. Platinum pentafluoride i s produced by the photolysis of platinum hexafluoride, osmium pentafluoride and iridium tetrafluoride are produced i n a similar manner. Above i t s melting point (80°), platinum pentafluoride undergoes disproportionation into platinum hexafluoride and platinum: tetrafluoride: 2PtF_ 5J  »- PtF„ + PtF. 6 4  88.  Cady and Hargreaves (103) have shown this to be typical of the transition; metal pentafluorides. The noble metal pentafluorides and rhenium pentafluoride a l l exhibit very high surface tension effects.  The molten fluorides resemble molten;  sulphur i n forming spheres which do not "wet"  glass.  They are also generally  viscous and after having been melted, c r y s t a l l i z e very slowly, often forming glasses.  Platinum pentafluoride i s no exception to this behaviour.  Edwards and Peacock (103) have made the only structural investigation! of these compounds by x-ray diffraction-methods.  They investigated molybdenum  pentafluoride by single crystal methods and found that i t was with two molecules per unit c e l l .  monoclinic  They found two different, types of  fluorine atom, and as there was no evidence for a bimolecular suggested an ionic structure of the type (MoF*)  (MoFg ).  species  This would be  consistent- with the ready disproportionation of the species. that; this might be a general pentafluoride structure.  They suggest  Conductivity measure-  ments on vanadium pentaf luoride and certain* non-metallic pentaf luorides (105,) have demonstrated the» existence of autoioniizationi iin the melts: 2 XF ; &  XE*  •*-  XFg"  It i s probable that platinum pentafluoride would also ionize i n this manner. If we now  consider the chemicalxproperties  of these compounds, the  pentafluorides of niobium, tantalum, ruthenium, osmium and iridium have a l l been shown, to form 1:1 adducts with bromine t r i f l u o r i d e (106).  The  platinumi  compound i s somewhat different i n that i t reacts to form.a 2:1 bromine t r i f l u o r i d e , platinum tetrafluoride adduct.  On heating, this adduct.  decomposes into platinum tetrafluoride and bromine t r i f l u o r i d e .  This  89.  reaction! with bromine t r i f l u o r i d e shows that the pentafluoride of platinum; i s more reactive than the pentafluorides of the other members of the group, and can act as a fluorinating agent, towards bromine t r i f l u o r i d e , oxidizing this to bromine pentafluoride.  The reaction between platinumi pentafluoride  and selenium tetrafluoride was not studied, but the corresponding reactions with platinum tetrafluoride, platinum-hexafluoride  and PtO^Fg a l l yielded  the 2:1, selenium tetrafluoride, platinumi tetrafluoride adduct. probable that platinumi pentafluoride would do the same.  It is  Corresponding  1:1 metal pentafluoride, seleniumi tetrafluoride adducts are knowni for the pentafluorides of osmium and iridium,: these are both low melting solids which decompose at their melting points into (MF ) &  2  SeF adducts (107). 4  Adducts corresponding to the iodine pentafluoride and chlorine t r i fluoride adducts of platinum pentafluoride have not been, reported for other members of the platinum group.  Similar adducts are however known for  the pentafluorides of antimony, with both iodine pentafluoride and chlorine t r i f l u o r i d e , and arsenic with chlorine t r i f l u o r i d e .  The formation of  platinum pentafluoride complexes with these donors reflects the greater resistance of iodine pentafluoride and chlorine t r i f l u o r i d e to fluorinatiom compared to bromine t r i f l u o r i d e . The great reactivity of platinum pentafluoride has hindered work on this compound considerably, as i t has on the other known pentafluorides. Unless great strides are made for handling such compounds, i t seems unlikely that any further structural information w i l l be obtained.  90.  POTASSIUM FLUOROPLATINATE (V) TABLE XVI.  Potassium salts of the MF„o ion.  KVF, KNbF KTaF  KMoF 6  6  KWF.  6  KReF,  KOsF, 6  KlrF, ""6  KPtF, 6  The known potassium salts of the MFg (v) ioni are l i s t e d im Table XVI. Those of niobium, tantalum, molybdenum, tungsten and rhenium a l l have the potassium fluoroniobate (v) structure - this has a tetragonal (pseudo-cubic) unit c e l l (103).  Those of vanadium, ruthenium, osmium, iridiumi and p l a t i -  num have the rhombohedral barium f l u o r o s i l i c a t e , or distorted caesiumi chloride, structure (109);  with regular, , or near regular, octahedral co-  ordination of the metal by fluorine atoms. Potassium fluorosmate (V), f l u o r i i r i d a t e (v) and fluororuthenate (V) a l l interact rapidly with water with the^ evolution of oxygen, and the formation of the corresponding fluorometallate (IV) ion; hydrolysis to the hydrated dioxide of the metal concerned occurs slowly. i s found with potassium fluoroplatinate (V).  A similar behaviour  The reduction.of the MFg~~ (y),  ion presumably occurs by an electron being transferred from the water through the coordination, sphere of fluorines around the metal: F F \.V/  \  F  <  F' M F  IV  2H  1  1/2 0  c  91.  Any other mechanism must invoke either- temporary reduction of the coordination sphere to 5.. ( S ^ ) or an increase to 7 (S^ ) , both of which 2  would be expected to lead to a complete break-dowm of the ion rather than, a reformation of the fluorine octahedron.  Further, the MFg  anion, can-  not be formed i n aqueous solution and the hydrolysis of this species i s an exothermic process (7). The l a t t i c e constants, of the potassium salts of the noble-metal fluorometallate (v) ion, l i s t e d i n Table XVII indicate that the fluoroplatinate V ion i s approximately the same size as the corresponding MFg ions for ruthenium, osmium and iridium.  This similarity i n size i s  further demonstrated by the near identity of the powder patterns as can be seen i n Plate 3, where the x-ray powder photographs of potassium fluororuthenate (V) and potassium fluoroplatinate (v) are compared. TABLE XVI1.  Lattice constants _ of some KMF„ structures  KRuFg (109)  4.97  97.4  KOsFg (109)  4.991  97.18,  KlrFg (109)  4.98.  97.4 . .  KPtFg  4.87  9,7.7  /  4 - this work.  A similar resemblance i s seen.when comparing the infra-red absorption peaks of potassium fluoroplatinate (v) with those of potassium fluorosinate (V) and potassium fluori. ridate (v)s  3.  1.  2.  PLATE3.  1.K PtF 2.KPtF 3.KRuF 2  6  6  6  92.  KOsFg (34) 0 3  KlrFg (34)  616  KPtFg  667  640,590 cm"  1  Thus, i n both i t s physical and chemical properties, potassium fluoroplatinate (v) behaves as we would expect:, from i t s position i n the group. PLATINUM OXYTRIFLUORIBE This compound i s characterized by i t s great, inertness.  For a penta-  valent compound this can. only be explained in.terms of the material being polymeries F 0  F  — P t —  I  F  F 0  F  -^Pt —  0  I  F  It bears no resemblance to the other MOF  compounds VoF o  ReOF ( H I ) .  (llO) and o  y3  PLATINUM HEXAFLUORIDE The preparation and properti.es. of platinum hexafluoride, and a number of other hexafluorides of the heavier transition.metals, have been fullydescribed i n a series of papers by Weinstock and his coworkers (19, 20, 112, 41, 113,  114).  They found platinum hexafluoride to be one of the least, stable of the hexafluorides and, because of i t s great reactivity, have found working with i t very d i f f i c u l t .  I t is a very powerful oxidizing agent and they  report (112) that i t w i l l oxidize neptunium and plutonium tetrafluorides to their respective hexafluorides and bromine t r i f l u o r i d e to bromine pentafluoride.  They did not state what the non-volatile reaction product.in  the last reaction was, but by analogy to the experiment performed with selenium, tetrafluoride i n this work i t i s l i k e l y that they obtained the bromine t r i f l u o r i d e adduct of platinum tetrafluoride.  Likewise i n the  reaction performed between platinum.hexafluoride and selenium, tetrafluoride i n this investigation., where the selenium tetrafluoride, platinum tetrafluoride adduct was obtained, i t i s probable that the selenium, tetrafluoride was oxidized to selenium hexafluoride.  The reactions beings  PtF_ +  3 BrF_  - PtF. ( B r F )  0  •+- BrE_  PtF  3 SeF.  - P t F . (SeF.)  n  + SeF  e  6  4  0  4  4 2 7  fi  6.  The physical properties of platinum hexafluoride have been showni to follow the pattern set by the other hexafluorides of the group (112).  94.  PtOJF  2 o c  PLATINUM PEROXIDEHBXAFLUORIDE  Whenever high temperature  f l u o r i n a t i o n s of platinum metal were c a r r i e d  out i n g l a s s or s i l i c a apparatus, or i n the presence of oxygen, high, y i e l d s of a deep red v o l a t i l e s o l i d were obtained. vacuum at 90°.  This m a t e r i a l sublimed i n a  I t reacted, with extreme vigour, with water to l i b e r a t e  ozone s m e l l i n g gases.  Benzene and other organic solvents immediately  caught  f i r e i n contact with the s o l i d , but i t n e i t h e r reacted with nor d i s s o l v e d ini carbon t e t r a c h l o r i d e .  These p r o p e r t i e s and the mode of preparation! indicated  that i t was a f l u o r i d e or oxy f l u o r i d e of platinum with the platinum i n a very high o x i d a t i o n s t a t e . Great d i f f i c u l t y , however, was experienced i n c h a r a c t e r i z i n g t h i s compound because of i t s great r e a c t i v i t y and the problems associated with i t s analysis. I n i t i a l l y analyses were c a r r i e d out by dropping a weighed quantity of the m a t e r i a l i n t o a 5$ sodium carbonate s o l u t i o n and q u i c k l y stoppering the f l a s k , when a l l r e a c t i o n was considered to be complete, f i l t e r e d o f f i g n i t e d and weighed as platinum metal.  the p r e c i p i t a t e was  The s o l u t i o n was made  up t o a standard volume, a l i q u o t s were taken and these were analysed f o r f l u o r i n e , by p r e c i p i t a t i o n as lead c h l o r o f l u o r i d e a f t e r a W i l l a r d and Winter distillation, acid solution.  and f o r platinum by p r e c i p i t a t i o n with zinc i n h y d r o c h l o r i c I n c o n s i s t a n t r e s u l t s were obtained, the most c o n s i s t a n t  of which suggested the formula PtOF^ (115).  Whem the p h y s i c a l and chemical  p r o p e r t i e s were i n v e s t i g a t e d f u r t h e r , they were found to be i n c o n s i s t a n t with t h i s f o r m u l a t i o n .  Further a n a l y t i c a l schemes were then  sought.  95.  F i r s t the compound was decomposed by breaking a f r a i l bulb containing a known weight of material into 5$ sodium carbonate solution i n a sealed jar, allowing this to stand overnight and them analysing as above, using finely granulated zinc for the precipitation of the platinum metal.  The  results obtained by this method were agaim inconsistant but showed am increase i n the percentage fluorine and a decrease in; the percentage platinum. The pyrohydrolysis method was then tried and i t gave consistant results. It was f e l t however, that due to the greats reactivity of the compound, some fluorine could be lost i n transferring the material to the apparatus. Accordingly the fluorine composition was checked by fusion with sodium metal i n a Parr bomb.  The fluorine analysis by this method agreed with  that from the pyrohydrolysis.  As a safeguard against low platinum, analyses  due to platinum being lost as a v o l a t i l e higher oxide (52) during the pyrohydrolysis, the platinum' was checked by weighing a quantity of material into a platinum crucible and them roasting this i n an atmosphere of hydrogen to constant weight.  The results obtained by this method were i n very good  agreement with those obtained from the pyrohydrolysis.  Having established  the percentage platinum and fluorine present, the other element present had to be established.  From the mode of preparation; of the compound, this  could only be oxygen; or s i l i c o n . formulation PtOJ?„ or PtSiF^. 2 o o was observed on hydrolysis.  The analyses were consistant with the The latter seemed unlikely because no s i l i c a  That the other element present, was oxygen was  shown f i r s t l y by synthesis, by fluorination of platinum dioxide i n a nickel apparatus using oxygen as the diluent gas;  and then quantitatively by dis-  placing the oxygen with bromine t r i f l u o r i d e i n a s i l i c a apparatus.  The  96i.  evolution of approximately one mole of oxygen per gram mole of material confirmed the formulation PtO_F . 26 e  Attempts were made to ascertain the valency state of the compound using the method of Crowell and Yost (116) but this could not be applied due to the variety of valency states produced on hydrolysis. It was hoped that an indication of the valency state could be obtained from a magnetic moment study.  However, no simple theory i s at present,  capable of explaining magnetic data, especially i n the second and third transition series.  Magnetic data i n the f i r s t transition series have  been largely explained by the theory of Kotani (117), but more recently (118) i t has been shown that two of the basic assumptions of the Kotani theory, (i) and ( i i )  that Coulomb repulsion i s much stronger than spin-orbit coupling, that magnetic interaction between ions i s negligible,;  are not satisfied by 4d and 5d electrons. The magnetic moment obtained (yU ^ 2.45. Bohr-magnetons) i s consistant with either two or three unpaired electrons,, the former being the most, likely. The quantitative gas evolution experiments are consistant with the empirical formula PtO^Fg, although the oxidation of water with the consequent, reduction of platinum to the quadripositive state would be expected to liberate 1_- moles of oxygen, per gram mole of material according to the equation: PtOgFg + H 0 2  * J?t * + A  6F" 1- 2H* +1%  0^  9 7 .  In practice, however, less than this quantity was obtained, this i s possibly explained by the formation of hydrogen peroxide under the conditions of the experiment. The x-ray crystallographic data clearly indicates that the platinumi atoms are at the points of a simple cubic l a t t i c e , a -s. 5.016°i.  Faints  superlattice reflections, however, show that- the oxygens and fluorines cannot have such a simple l a t t i c e .  They can, however, be represented by  a unit c e l l eight times this size (p.58).  This situation i s akin to that;  described by Zachariesen (119), who found that i n the lanthanum oxyfluoride structure, the lanthanum atoms were on the points of a cubic l a t t i c e but the oxygens and fluorines were on a l a t t i c e of lower symmetry.  In the  platinum oxyfluoride structure, the average volume occupied by the oxygen: o3 and fluorine atoms i s 15;.9A , which indicates very close packing.  Zachariesen  (120) reports values varying from 16.9 to 19.4& for the volume of the fluoride 3  ion i n the uranium fluorides. The mass spectrographic evidence was of limited value as mass numbers above 245, could not be observed on the instruments available.  However, a  definite indication of two oxygen* atoms linked to one platinum atom wasobtained. The infra-red spectrum i s complex,, and no attempt was made to assign frequencies.  I t does, however, indicate that the molecule of low symmetry  and the spectrum shows very l i t t l e resemblence either to that of platinum hexafluoride (20) or that of the hexafluoroplatinate (V) ion.  There i s also;  no peak, i n the region* between 700 and 1000 cm""*, which i s the region where one would expect to find an 0-F stretch (0-F s OF , 928 (121, 122); Sp F0F o  879(123); SF OF, 888(124);  SeF OF, 925 cm  -1  (125)).  98.  I t seems, then unlikely that the compound contains at. Pt-O-F bonds. In i t s chemical behaviour, PtO^F^ behaves as a very powerful oxidizing agent.  The reaction with bromine t r i f l u o r i d e has been mentioned  i n connection with i t s value i n the confirmation of the formula.  earlier The  other product of the reaction i s the 2:1 bromine t r i f l u o r i d e platinum, tetrafluoride adduct, i n this instance then the bromine t r i f l u o r i d e must, be acting as a reducing agent.  Similarly selenium tetrafluoride acts as  a reducing agent i n reacting with PtO^F^ to form the 2:1 selenium tetrafluoride, platinumi tetrafluoride adduct.  Iodine pentafluoride reacts to  give a platinum pentafluoride adduct, however, and the best way to prepare potassium hexafluoroplatinate (v) i s by interaction of the oxyfluoride and potassium fluoride i n this solvent..  This salt i s also produced when, the  oxyfluoride i s sublimed over potassium fluoride under vacuum. What then are the l i k e l y structures for this compound? The following have been considered:1.  F  OF | ^ Pt, F^"^ | ^ \  OF  This structure i s consistant with the magnetic F F  data i n that six valent platinum i s l i k e l y to be paramagnetic with two unpaired electrons.  It i s however inconsistant with the fact that no 0-F stretching frequency i s observed, i n the infra-red spectrum.  This.also does not explaini  immediately why platinumi coordinated by six fluorines i s found i n the fluoroplatinate ion i n solution. 2.  The ionic formulation VtF^Q*  .  Thisraost unlikely formulation .could  explaini the magnetic properties of the compound, for although the platinum.  99.  i n this compound would be i n the five-valent state the singly charged 0* ion would also have one unpaired electron.  With such a compound, however,  dissociation into the components 0,F and PtF_ would be expected on sublimao  tion.  The fact that the compound sublimed completely and could be quanti-  tatively transferred argues against t h i s . This formulation i s inconsistant with both the magnetic 3.  FgPt  ^ properties and with the infna-red spectrum.  Such, a  structure would involve a l l ten. valence electrons i n bonds with the result', that i t would be diamagnetic. 4.  F_PtC ^0 \  on-  6  - i.e.  platinum  0^ > F _ P * r ^0 \ — 0 ^ 6  0  p t F  ft» 6  0  peroxidehexafluoride.  This formulation, either as a monomer, or as a polymen, would account for most of the properties of the compound.  I t would involve octa-positive  platinum, which would necessitate two unpaired electrons - this i s consistent with the magnetic data.  The fact that the material sublimes readily suggests  that i t i s compos.ed of discrete low molecular weight molecules. evidence allows the monomeric. formulation only.  The x-ray  The great reactivity and  oxidizing properties of the compound and the existence of ozone smelling gases on hydrolysis  - though no ozone was detected i n the infra-red spectrum «f  the gases evolved - are also consistent, with this formulation.  A molecular-  weight, determination on.the material was not possible. This compound w i l l then, be knowm as "platinum peroxide hexafluoride".  100  THE COMPLEXES OF QUADRIPOSITIVE PLATINUM Writing, once more the l a t t i c e dimensions of the selenium tetrafluoride adducts of platinum tetrafluoride, palladiumi tetrafluoride and germaniums tetrafluoride* PtF a c.  (SeF )  4  4  PdF  2  15.74  (SeF )  4  4  GeF  2  15.47. 4.88  4.93  (SeF )  4  4  15.60 4.93  2  i  i  It i s seen that these form an isomorphous series, similar to the isomorphous series of the salts of fluoroplatinic, fluoropalladic and fluorogermanic acids; e.g.  K PtF 2  a c  (32)  6  K PdF 2  5.76  6}  (78,79)  K GeF (l26) 2  5.72 4.67  4.641  6  5.62, 4.65  1 1  It would appear, then, that the selenium tetrafluoride complexes can be regarded as salts of the respective fluorometallate (IV) anion with the cation SeF*  - i.e. (SeF ) g  2  PtF , ( S e F ^ &  PdFg, ( S e F ) g  2  GeFg.  The s a l t - l i k e character of these compounds i s evid ent i n tha t they do not melt on heating, but on heating to a sufficiently high temperature,, they, break-down, into their components.That selenium tetrafluoride i s capable of autoionization to give the SeF*  cation. 2SeF. 4  ___ SeF* + 3  SeF ~ 5>  has been shown by conductivity studies. ( 9 4 ) . Bromine t r i f l u o r i d e and iodine pentafluoride have also been showni to be ionizing solvents by conductivity measurements. (127): 2BrF ' BrF * + BrF " 3 2 4 2 IF, . 5  1F.  +  4  1-  IF " 6  101  These solvents also form.adducts from solution.  The adducts formed  with these compounds} however, are usually found to be low-melting, to c r y s t a l l i z e only with d i f f i c u l t y and to decompose at relatively low temperatures, usually evolving the respective solvent, and leaving behind a fluoride of the metal concerned.  The 2:1 bromine t r i f l u o r i d e platinumi tetrafluoride  adduct i s typical i n this respect i n that i t melts at 130° and readily decomposes above t h i s temperature to y i e l d platinum tetrafluoride, %yith the evolution of BrF„. o  These solvents do not appear to form salts of isomorphous acids as do the selenium tetrafluoride compounds - e.g. (BrEg) P^Fg, ( B r F ) GeF,g 2  but (BrFg) PdF^.  2  2  In the case of the palladium compound, this fact i s  particularly striking, as the 1:1 bromine t r i f l u o r i d e palladium tribromide compound reacts with potassium, fluoride and with selenium tetrafluoride to yield the potassium and fluoroselenonium salts of fluoropalladic acid respectively (78): 6 BrF , PdF. +12 Q  6 BrF } PdF_ o  o  KBrF-  12 SeF.4  6 K PdF„ + Br  + 16 BrF„  6 ( S e F ) PdFg + B r -f- 4 BrF . 3  2  2  g  Thus, the bromine t r i f l u o r i d e complexes would appear to be considerably more covalent i n nature than the corresponding selenium compounds..  The  fact that the platinum compound gives rise to the fluoroplatinate (IV) iom i n solution, however, shows that the platinum, must be coordinated fluorines.  by six  I t would seem, then- that these compounds are best written! ini  terms of the covalent structures:F  F  102.  This i s i n contrast to the ionic structures proposed for the selenium tetrafluoride compounds!-  E  F I  Pt  Se F  J  2  | F  ^ F  etc.  These formulations would best be checked by a nuclear, magnetic: moment study of the compounds.  103.  THE TETRAFLUORIDES Zachariesen  (128) had shown that the tetrafluorides of ceriunr, terbium*  zirconium, hafnium and the actinide elements were ized i n the monoclinic  isomorphous and c r y s t a l l -  system, and a complete structure determination! of  zirconium tetrafluoride had been made by Burbank and Bensey (129).  When,  i t was found that platinum tetrafluoride did not c r y s t a l l i z e i n this system, but had a uranium; tetrachloride-type of structure, i t was decided to investigate the other- knowni tetraf luorides to determine the importance of this- l a t t i c e . The known saline tetrafluorides are l i s t e d in\ Table XV111.  Those of  manganese and osmiums had not beem established at that time, that of iridiumi was thought to resemble the pentafluorides more tham the tetrafluorides and those of chromium and vanadium were under investigation, i n other parts of these laboratories.  As a start; to this project, the tetrafluorides of  rhodium.,tin and lead were investigated and i t was found that no two structures were alike (see Plate 2).  Crystalline samples of rhodium tetrafluoride  were obtained only with great; d i f f i c u l t y , and the x-ray pattern was indexed on the basis of a face-centred, cubic unit c e l l containing 16 molecules. Tin tetrafluoride was found to be tetragonal, the unit c e l l containing 8.. molecules.  Lead tetrafluoride, despite earlier reports (85.), which indicated  that i t was tetragonal, gave a complex powder pattern andno attempt, was made to index i t . Subsequent reports have indicated that the structure of rhenium*tetrafluoride i s complex ( i l l ) and although osmium.tetrafluoride firmed, no structural data has been given (104).  has been con-  P L A T E 2.  S O M E T E T R A F L U O R IDES  1.PtF  4  2.RhF  4  3.SnF4 4.PbF4  104.  TABLE XVI11. TiF (l30) VF (131)  CrF (l32)  ZrF (l28)  MoF (l0l)  HfF.(l28)  WJ134)  4  4  4  Rare Earth:  The known.saline  tetrafluorides  4  4  CeF , TbF (128) 4  4  Transuranic: ThF , UF , NpF , PuF , AmF (128) . 4  4  4  4  4  Thus, we see that the tetrafluorides are capable of c r y s t a l l i z i n g i n a variety of different, l a t t i c e s , and no set l a t t i c e type, other than that of zirconium tetrafluoride i s predominent. The infra-red spectra of the tetrafluorides investigated are tabulated, together with those of the previously investigated tetrafluorides i n Table XIX. The peaks obtained are tentatively assigned as being \) , the assymetric g  stretching frequency.  Direct comparison between the sets i s not real how-  ever because the earlier results were of materials i n the gas phase, while those reported here are for nujol mulls of the materials concerned.  The  latter method results i n a vast broadening of the bands as compared with the sharp peaks- obtained for the spectra of materials i n the gas phase.  105.  TABLE XIX.  CF (135) 4  SiF  4  (135, 83)  GeF (135) 4  Infra-red  spectra of some tetrafluorides  -*1 904  435,  >) 3 1283  634  800  268  1031  391  740  200  800  260  Z r F (136)  668, 670  H f F (136)  645), 650  4  4  TbF (136) 4  520  PtF„ ^ 4  576, 674  PbF„ ^ 4  4552, 640  SnF ^  5.75-6941  RhF. ^ 4  550-678  4  /  this v/ork.  190  10.6.  THE FLUORIDES OF PALLADIUM The lower fluorides of palladium have recently been reported in; detail (78).  The attempts made in. this, work to prepare a higher fluoride of palla-  dium than the well characterized t r i f l u o r i d e resulted in, failure, the same products being obtained as were obtained by Ruff and Ascher (38).  It i s  f e l t however, that'the formation of some palladium difluoride i n the fluorination* of palladium metal i s due to sintering, not to localized heating as ascribed by Ruff and Ascher.  Weinstock et al (114) were also unable to  prepare a higher fluoride of palladium than.the t r i f l u o r i d e .  These workers  tried heating palladium metal, with an induction heater, in; a n i atmosphere of fluorine i n a liquid nitrogen-cooled quartz reacter.  This was the same  method that had been successful i n the preparation of the other hexafluorides: of the group. It would seem, then, that a hexafluoride of palladium cannot be prepared.  This i s not too surprising i n view of the i n s t a b i l i t y of the  hexafluoride of i t s nearest neighbour, rhodium (114).  However, from i t s  position i n the Periodic Table, a higher fluoride than; the t r i f l u o r i d e of palladium would be expected.  10 T.  THE FLUORIDES OF RHODIUM The brief investigation of the fluorides of rhodium resulted from attempts to obtain, a sample of rhodium tetrafluoride crystalline enough; for structural determination. The pale-pink rhodium fluoride, bromine t r i f l u o r i d e adduct formed by reacting rhodium tribromine with bromine t r i f l u o r i d e had been mentioned earlier by Sharpe (7), but he was unable to isolate i t .  This compound  was isolated during this investigation, but analyses of i t were inconsistent.  They did, however, suggest that i t was a l s l complex between  bromine t r i f l u o r i d e and a fluoride of rhodium.  The diamagnetism of the  compound indicates the formulation RhE , BrF .  Tripositive rhodium has  Q  a d  configuration, and this would be consistent with the observed diamag-  netism.  Quadripositive rhodium, on the other hand, has a d  configuration  and so would be expected to be paramagnetic. The v o l a t i l e , orange compound produced by the fluorination of rhodium metal or rhodium tetrafluoride i s very reactive. i t attacked the s i l i c a tube very readily.  During i t s preparation,  I t also reacted violently with  water to y i e l d a deep-blue solution and precipitate. sufficient, of this material was available for analysis.  Unfortunately i n The behaviour of  this compound i s i n marked contrast to the behaviour of rhodium tetrafluoride prepared by the method of Sharpe (7).  The latter does not melt, and iis not  v o l a t i l e , i t can be handled i n moist a i r for short periods of time without decomposition. and precipitate.  I t does react with water, however, to give a green solution! I t would seem then, ithat the volatile red-brown compound  obtained on fluorination of rhodium metal, and as described earlier by Ruff and Ascher (38), was i n fact rhodium pentafluoride and not rhodiumt tetrafluoride as designated by Sharpe (7).  10 8.  That the deep red vapours seen above rhodium metal and rhodium tetrafluoride on fluorination were rhodium hexafluoride has been given support, by the recent isolation of the very unstable rhodium hexafluoride by Weinstock, Claasen and Cbernick. (114), who prepared i t by burning rhodium metal i n an atmosphere of fluorine and condensing the vapours on a surface cooled with l i q u i d nitrogen situated directly above the reaction zone.  They describe  this compound as existing as deep-red vapours or as a black solid, which rapidly decomposes at room temperature into a lower fluoride and fluorine. GENERAL DISCUSSION Since this work was  started, several important contributions  concerning  the fluorides of the neighbouring elements to platinum have been; made. Hargreaves and Peacock (104), have characterized the fluorides of osmium: and have proved that the compound tentatively assigned as osmium: pentafluoride in Table 1 i s i n fact the pentafluoride, they also suggest that the compound that Ruff and Tschirch (40) referred to as osmium^pentafluoride i s in. fact osmium dioxydifluoride or osmium; t r i f l u o r i d e .  Weinstock et al (113,  114)  have, prepared and characterized the two very reactive hexafluorides of ruthenium and rhodium. Further advances have also been made i n the fluorine chemistry of the other transition metals.  Malm, Selig and Fried (137) have succeeded in.  preparing the f i r s t simple septavalent fluoride, that of rhenium.  Hargreaves  and Peacock (103) have described the preparation! and properties of a pentafluoride, tetrafluoride, oxytetrafluoride and oxytrifluoride of rhenium. More recently, Klemm et al (133) have prepared manganese tetrafluoride, a compound that had been suspected for some time but which had not previously been.isolated.  Prior to this the drop in maximum valency from five for  10S.  vanadium and chromium to three for manganese i n i t s simple fluorides had seemed rather great, though manganese had previously exhibited the septapositive state i n forming permanganyl fluoride. In spite of these recent, changes, the overall trend i n the. fluorine chemistry of the transition metals outlined i n the introduction remain unchanged.  The position of the maximum oxidation state i n each transition,  series i s shifted to higher atomic number as we pass from the f i r s t to the second to the third transition series.  The fact that there i s a change  i n maximum valency of three units in;moving from rhodium to palladium, and again from platinum to gold, seems rather anomalous.  Further investigation  may however reveal higher fluorides for. these metals. SUGGESTIONS FOR FURTHER INVESTIGATIONS From this investigation, certain topics at once suggest themselves as being f r u i t f u l for further study:1)  An attempt to prepare further adducts of iodine pentafluoride and chlorine  t r i f l u o r i d e with other transition metal fluorides.  This should be accompanied  by a study of a l l adducts of this type using nuclear-magnetic resonance techniques to ascertain the types of bonding i n these compounds. 2)  A reinvestigation of the fluorides of rhodium, with a particular- view to  characterizing the suggested pentafluoride - this may prove very difficult.due to the great reactivity of the compound.  An oxyfluoride analogous to platinum  peroxidehexafluoride should also be looked for. 3)  An investigation into the p o s s i b i l i t y of forming peroxidehexafluorides  with a l l those elements forming v o l a t i l e hexafluorides, by carrying out the fluorinations using oxygen, as the carrier gas. 4)  The preparation and structure determination of other salts of fluoro^  p l a t i n i c acid (v).  SUMMARY  110.  SUMMARY OF THE KNOWN FLUORIDES OF PLATINUM Formula  Colour  PtF,  Gn.-yellow  PtF,  Black  Magnetic — T — Moment r r - -  3  -  Structure  Rhombohedral a = 5.41:  PtF.  Yellow  Diamag.  PtF  Deep red  Paramag,  Red-bn. vapour  PtF,  t0 F 2  A  „0  Monoclinic a _ 6.668; c _5.708s if =92.02  Sublimes 300  1-17, 7/  m. 80 b.c.c. a -6.209  m.  56.7  0  19.20,112?  black solid  PtOF„ p  Ref. —— 1,2,6,12  I-  e  Other properties  Light, bn. 6  Orange-red  2.45B.M. Cubic a = 5.016  m.2l9°(d) Sublimes 90*  Diamag.  m. 130 (d)  7,/  Dec. 350°  16,  Adducts PtF (BrF )  2  PtF (SeF )  2  4  g  4  4  Red; Lt.-orange  PtF_,lE_  Orange  PtF_,ClF„ o o  Yellow-orange  PtF ,SF ?  Buff  Pt(C0) F  Pale-Yellow  5  4  2  g  Diamag.  0.65B.M.  .'Hexagonal a _ 15.74'; c =4.93  m. 160 (d) m. 171°(d)  7*  Dec. 180°  Sublimes 70  95  Formula Salts H PtF 2  K  Colour  n  6  P t F  Structure  2 0  Solubility/  Diamag.  4.83  0.750  7,17,2125, 28, 30-32,3'  6.00  0.278  7 , 2 S , 28. 30-32!.  Trigonal a = 6.22  5.39  0.484  7,25), 28 30-32  Hexagonal a = 9.41 c •= 5.165  4.21  20.49  -  -  28  3.59  7.32  21,  2.63  7.5,  26  Trigonal a a, 5 . 7 6 =4.64  it  PtF o ft  —  Trigonal a 5.96 =  x4.83  c  Cs  PtF  2  II  6  —  C; = 5 . 6 1  Na  L i  PtF  2  2  P t F  (NH )  tt!  6  -  6  PtF  6  (PtF )  3  Pr,  (PtF )  3  Nd  2  (PtF )  3  Ce  2  (PtF )  3  4  La  2  2  6  2  6  6  6  Mg PtFg 6H 0 2  Ca PtF  ft  Ref.  100g H 2 0  27  c  Rb  S.G.  Pale-yellow  6  2  Magnetic Moment  6H 0  o. 2 Sr PtF„ 2H 0 o 2  Pale-yellow tt.  tt.  tt.  Pale-yellow It;  —  28,30  -  -  -  2.64  7.1  26:  -  -  2.66,  6.6  26  -  -  -  26i  -  -  2.65.  67.9  29  -  -  4.13  104.9  29  Rhombohedral a 4.74  4.42  98.6  29,  33  Rhombohedral  6.04  0.171  29,  33  5.11  Dec.  II:  -  -  28>  =  ««• = 9 7 . 8 ,  Ba PtFg  tt:  —  =4.88 =98°  a oc  E PtF o c  Yellow  0.87  B.M. Rhombohedral a = 4.87 oc  /  this work.  =  97.70  APPENDICES  .112-  APPENDIX 1. AN ALWAC H I E COMPUTER PROGRAMME FOR DETERMINING USEFUL FUNCTIONS FROM X-RAY POWDER PHOTOGRAPHS Introduction The "reflection" of x-rays by a crystal l a t t i c e only occurs when; the Bragg equation, 2 d sin 6  =  A  is satisfied. 6  angle of incidence  d  interplaner spacing  h  warelength of radiation used.,  If we consider an x-ray powder photograph, the distance between; any w i l l correspond to 4 6  pair of lines; (<> x  and i s related to the  radius of the film (R) by, X g  - i j = 4 6. R.  where 6 here i s measured in.radians. Thus, 0 v/alues of  may be determined from a knowledge of R. and the measured a  nd x^  #  By substituting this value of © i n the Bragg equation*  d may be determined. From a consideration of the reciprocal l a t t i c e , i t can be shown; that, ^ C  ^,  =  r.2 *2 „2. .*2 ,2 *2 h a +• K b + 1 c; * 2hka*b*cos <Jf * + 2klbfc*cos + 21hc c a cos^S  Where, c5" hkl i s the reciprocal l a t t i c e vector and a*, b*, c*, <=**, jS and are the reciprocal l a t t i c e Now,  dimensions*  _fhkl Qhkl  or,  8  -  l/dhkl l/d hkl 2  =  combining with the Bragg equation^  ©hkl ~ l/d 2 hkl Now,  =  4 sin  2  6hkl/?> _ const, x s i n 2  2  ehkl.  each line of a powder photograph corresponds to a reciprocal  l a t t i c e vector.  Thus, the f i r s t step i n interpreting a powder photograph  i s to select, from the l i s t of Q edges a , b , c .  values, values of the reciprocal c e l l  These values are then checked against the experimental  values by using these to compute a complete set, of Qhkl values according to the above equation. aim  6 values or 1/d  This may be carried out by a comparison of either values.  The actual c e l l edges may theni be computed  from the reciprocal c e l l edges. Nelson and Riley (63) have sho.wni that for cubic crystals, the main, source of error i n the determinatiiont of the l a t t i c e parameter i s due to absorption, and found empirically that this could be best overcome by cos B plotting values of a againstL the functional.- ( . . 2  s m  D  H  cos © —) 2  o  and extrapo-  lating the value to 90°', where the error due to absorption i s zero.  This  function has since been used by other workers (138, 139, 140) for the determination of accurate l a t t i c e parameters for tetragonal and hexagonal systems. The programme to be described was written to process data obtained from x-ray powder photographs.  Values of the wavelength, of radiation used,  radius of the film and values of pairs of computer and values of  x^>  Xg»  x^  x^ and  Xg are input into the  Xg» © ( i n degrees) sin ©, d, l / d 2  2  and the Nelson-Riley function, are output. Input routine The programme, which i s to be stored i n channels de-eo of the computer, i s f i r s t read into the computer from the programme tape.  The  computer then, halts and awaits the input, of numerical- data, which i s then read i n by a separate data tape. The data tape should be punched out on. the Flexowriter i n the following form, deOO CR ft SP. R CR. x SP. Xg SP. x « SP. Xg * SP 1  CR.  1  etc. Where,  Xg i s the greater of the two values i n each case.  The  numbers may be punched in. i n any convenient form - 5.000, 5i, 0.125;, .125> etc. - and terminated either by a space (SP.) or a carriage return* (CR.) . Five sets of Any number of  x^, Xj,  Xg values can conveniently be accommodated on one l i n e . x  g  values can be processed im this manner, the data  should be terminated by a stop code. When a change of wavelength i s required - e.g. for Ko^ and K«g values a fresh data tape must be punched. Output The computer w i l l output results on the high-speed punch i f this i s on, otherwise results w i l l be output on the Flexowriter.  It i s preferable to  115  output, data on the high-speed punch, then print the results from this later.  Data i s output i n columns i n the form:  R x  x  x  g  % +• 1  x  2  6°  sin © 2  A typical calculation involving 50 minutes to compute.  d  x^,  1/d  x  2  g  N.R. fn.  pairs takes about six  The data tape for this takes about ten minutes  to punch and check. The programme i s giveni overleaf:  PJI7UPH7O 0 9 00000000 00000000 oooooooo-oooooooo 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000  oooooooo-oooooooo •oooooooo-oooooooo6«nootzo tgoooioo *lHlOOlEO ^ooootoo oooooooo-oooooooo •oooooooo-£q.qi76£oo 00002000 00090000 OOOtyXXX) 0000I000 03 JO£2  oooooooo-oooooooo •00000000-'B^6i70l£ B ,  OOOOOOOO-OOOOOOOO' OOOOOOOO-OOOOOOOO'  •OOOOOOOO-lrt^OfiHi  •oooooooo-9^6t[Oi  oooooooo-oooooooo •000086U oooooooo-oooooooo •B^jp^zli  OOOOOOOO-OOOOOOOO'  •00JP09U  zfi_9£iiqs 2£2,9ooo£ ^i9ooo£  oooooooo-oooooooo <XI<&J$QL oSq.3oi£,e oooooooo-oooooooo •«oSSJU8 00820+T l+r  J P JO£2 0^2JtJ9-tT 8 P  lQq?ol£v c_6i70t£T2 008ZO+7ti7 Ifi_ai5tl7  21820^^3  si_6Hl8-l  280£1£2.9 0t£«0092 0 9 U 6 l < _ 8^6i6^6-tj O+IHT£^6+T oiE^gogz Ol&eoQLs o^l-tTt^6-n 9 0 i 8 ° 6 i t o^oi^qp o l C ^ l t 6S8+T09U  09ll6ip_ JU&LSgn 9U8£^^ O^QJPtQ 3P J0£2  117.  APPENDIX 2. AN ALWAC H I E COMPUTER PROGRAMME FOR THE GRAPHICAL DETERMINATION OF ACCURATE LATTICE PARAMETERS FOR TETRAGONAL CRYSTALS. Introduction When attempts are made to determine l a t t i c e parameters for tetragonal or hexagonal crystals, there are three unknowns, systematic error.  Methods for determining  a, c and the d r i f t or  these include Cohens's least;  squares method (141) and the graphical methods of Taylor and Floyd (138) and Myers and Davies (139).  This programme was devised to assist i m  using the last method. The direct graphical method of Myers and Davies depends om finding the line best f i t for a series of straight lines ini three  dimensional,  space, each straight line being derived from a particular crystal l a t t i c e reflection.  In practice, a two dimensional  dimensional  projection of the three  situation i s adopted.  The Bragg equation when, applied to tetragonal crystals may be written in the following forms: (a/c) and  a  2  2 s  3  s i  s ft  2  »  2  ©/ *  2  *f7  & 2  " (  ( h +- k )/4 s i n 2  2  2  0  q 2  +  k 2  )/!  2  (general form)  (for hkO planes) 2  These are equations of straight lines ini variables a These may; be plotted for a givemO after indexing.  2 and (a/c) .  Ideally, the lines  would a l l intersect, at a point, but d r i f t and scatter must be taken into; consideration and the line of best f i t has to. be found.  This i s done by  constructing a fan diagram of the extrapolation function of the angles om  118.  transparent paper and moving this around on the plot u n t i l the line of best f i t i s found.  The horizontal line gives the ( a / c )  2  value and the  o # . 2 (from the fan diagram) gives the a value.  extrapolated value of 0 9 0 s  The d r i f t i s found by a subsequent plot - the third dimensional: 2 representation!- of the derived a  values against the Nelson-Riley  extrapolation function. Input routine This programme, which i s to be stored ini channels el and e2 of the computer, i s read into.* the computer, by the high-speed reader, from the programme tape.  The computer halts and then awaits the input of numerical  data, which i s input from; a separate data tape. The data tape should be punched out on. the Flexowriter int the following from', elOO CR. h  x  SP.  h  2  SP. k  SP. l 2  x  SP. 1  2  SP. 6 1 ° CR SP. 8 2 ° CR.  etc. and the data terminated by a stop code. Output routine The computer tests for 1 _. 0, computes the data and outputs the results i n the form:h  x  k  x  l  4 sin  x  and etc.  8/ >, 1  2  2  (h  2  }\ ( h + k ) /4 s i n £> 2  2  2  2  fc )/l  2  2  0  2  for hkl for hkO  119.  A typical computation involving f i f t e e n planes took approximately t h i r t y seconds to compute.  The data tape for this took approximately  three minutes to punch, and check. The programme i s given overleaf.  LtfVlSBQ. 2 00000000 00000000 00000000 00000000 00000000 00000000 oooooooo-oooooooo00000000 00000000 00000000 00000000 00000000 00000000 oooooooo oooooooooooooooo-oooooooo-00000000-60000111 oooooooo-oooooooo g^ootno 1122.10911 96000100 02000120 oHrooi2o 6Z<&Q£QL 90000100 9M00000 oooonooo lo££q6Ll 29 Jo£2 L&cayzL 19 ££990092 90^9176^1 $£QLlo^ 1£6IT0092 ££0-1712^ 9£9*i09H 3  PSqaoil'B v£Lzooo£ o£t9q£61 o£l9<\£6L 9£&v£q? z66ivzl9 ol£«oo82 *i£6L66Ll  12A90092 siLQ^IP O l W £ i . 3 0911^2^ j£^0liv nLQl£6ii •^sttozqi 09lt£2q£ 22lseoo£ s U 9 2 £ 9 19 J0£2 9  f  REFERENCES  121.  1.  H. Moissan, Compt. rend., 1889, 109, 807.  2.  H. Moissan, Ann. Chim. Phys., 1891(6), 24, 282.  3.  0. Ruff- and J . Zedner, Ber., 1909, 42, 1037.  4.  0. Ruff, Z.anorg. Chem., 1916, 98, 27.  5.  0. Ruff., Z. angew. Chem., 1928, 41, 738;.  6.  0. Ruff, Ber., 1936, 69, A 181.  7.  A. G. Sharpe, J . Chem. S o c , 1950, 3444.  8.  0. Ruff and J . 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O  N  2-°2  (Nl LL  FIGURE 3 Apparatus for reactions involving bromine trifluoride, selenium tetrafluoride or iodine pentafluoride  •a  a— I I  I  ID Ii O  CO  a >s\ > cnJi  FIGURE A  FIGURE  4  Apparatus for reactions involving oxygen difluoride, sulphur tetrafluoride or chlorine trifluoride >—• £ o o <u o Z. u) «- o in Li. -»-> Q) V) >  o  3  CM  CO  3T  3 JQ  E E  I J— o >» O  ZJ HM  o  I/)  FIGURE 5  Apparatus used for studing decomposition reaction.  B19 Cone & socket  1  To vacuum system  FIGURE 6  Apparatus used for preparation of P^  W -Q— CM  O CO  D  EZ3 ai  FIGURE 7  Apparatus used for purification of  Q:  "0=  — o  _Q  LO  if  «o °o w >* „  I— >  (/»  1  02Fg  FIGURE 8  A p p a r a t u s used f o r measuring g a s evolution  

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