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UBC Theses and Dissertations

New flourides of the noble metals. Rao, Ramesh Pathur 1965

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The U n i v e r s i t y of B r i t i s h Columbia FACULTY OF GRADUATE STUDIES PROGRAMME OF THE FINAL ORAL EXAMINATION FOR THE DEGREE OF DOCTOR OF PHILOSOPHY of RAMESH PATHUR RAO B.Sc. , Madras U n i v e r s i t y , India,, 1958 TUESDAY, SEPTEMBER 7 S 1.965 at 10:00 A.M. IN ROOM 261 5 CHEMISTRY BUILDING COMMITTEE IN CHARGE Chairman: G.H.N. Towers N. B a r t l e t t J. P. Kutney L. G. Harrison C. A. McDowell E. Tejghtsoonian External Examiner: H.J. Emeleus University. Chemical Laboratory U n i v e r s i t y of Cambridge Cambridgeshire, England NEW FLUORIDES OF THE NOBLE METALS ABSTRACT The compound previously i d e n t i f i e d as palladium t r i f l u o r i d e and as such accepted as the only unambiguous tervalent palladium compound, has been shown to be the mixed valence compound P d 2 + (PdFg)^". This has resolved d i f f i c u l t i e s associated with the d e s c r i p t i o n of PdF3 i n terms of c r y s t a l f i e l d theory. The synthesis of a new series of compounds of general formula P d 2 + ( M F 6 ) 2 ~ S isomorphous with P d 2 + ( P d F 6 ) 2 ~ and magnetically s i m i l a r to the l a t t e r has been achieved. The oxidation state of palladium excited by bromine t r i f l u o r i d e has been shown to be +4 when good f l u o r i d e ion donors are a v a i l a b l e ( i . e . when the s o l u t i o n i s basic) and +2 when good f l u o r i d e ion acceptors are present i n s o l u t i o n ( i . e ! i n acid conditions). Reasons for the i n s t a b i l i t y of Pd(III) i n a f l u o r i n e ligand environment are discussed. Antiferromagnetic ordering has been observed i n palladium d i f l u o r i d e . This has accounted for the low value of the room temperature magnetic moment of the compound. A less tedious synthesis, of palladium d i f l u o r i d e has been accomplished by the p y r o l y s i s of the new palladium (II) hexafluorogermanate ( I V ) s , a t temperatures above 350°. A t e t r a f l u o r i d e of palladium has been prepared for the f i r s t time. I t i s the highest valence binary palladium f l u o r i d e now known. It has a body centered tetragonal l a t t i c e and i s i s o s t r u c t u r a l with uranium and thorium t e t r a c h l o r i d e s . The adduct of palladium t e t r a f l u o r i d e with bromine t r i f l u o r i d e , (BrF3)2PdF^ s has been prepared and was found to be isomorphic with the corresponding platinum compound. The magnetic s u s c e p t i b i l i t y of gold t r i f l u o r i d e has been reinvestigated. A n a l y t i c a l l y pure AuF3 has been shown to be diamagnetic. This has unambiguously assigned a low spin d^ configuration for Au(III) i n gold t r i f l u o r i d e . Fluoroaurates (III) of sodium, potassium, n i t r o s y l a rubidium and caesium have been found to be diamagnetic. The s a l t s with the exception of CsAuF^. proved to be isomorphous. Also N O A U F 4 has been found to be isomorphous with N0BrF4-The existence of a t e t r a p o s i t i v e state of gold has been indicated. Gold t e t r a f l u o r i d e i s a pale yellow, highly reactive solid,, This f i r s t paramagnetic compound of gold i s amorphous to x-rays. The previously unknown pentapositive state of rhodium has been established. Rhodium pentafluoride i s a deep red s o l i d , m.p. 95,5° 3 and i s highly r e a c t i v e . I t reacts with carbon tetrachlorides chlorine monofluoride being among the products. I t i s s t r u c t u r a l l y s i m i l a r to ruthenium pentafluoride, but has a smaller molecular volume. A hexafluororhodate (V) has been prepared for the f i r s t time by reacting rhodium pentafluoride with stoichiometric amount of caesium f l u o r i d e i n iodine pentafluoride. I t i s s t r u c t u r a l l y s i m i l a r to the other caesium hexafluorometallates (V) of the noble metals. The h i t h e r t o unknown i r i d i u m pentafluoride has been established and i t s i d e n t i t y with the previously known iri d i u m t e t r a f l u o r i d e has been revealed, Iridium pentafluoride i s s t r u c t u r a l l y s i m i l a r to the other noble metal pentafluorides and i s almost isodimensional with ruthenium pentafluoride. It has magnetic properties t y p i c a l of t h i r d t r a n s i t i o n series d^ e l e c t r o n i c configuration i n an octahedral or near octahedral environment. I t i s suggested that i n both rhodium and i r i d i u m pentafluoride the s t r u c t u r a l unit i s a f l u o r i n e bridged tetramer as i n ruthenium pentafluoride. GRADUATE STUDIES F i e l d of Study: Inorganic Chemistry Physical Inorganic Chemistry H.C. Clark C. Reid Topics i n Inorganic Chemistry N.Bartlett W. R> Cullen Topics i n Physical Chemistry A. Bree J. A. R. Coope C r y s t a l Structures N.Bartlett J. Trotter Chemical Thermodynamics J.R. Sams Advanced Inorganic Chemistry H.C. Clark W. R. Cullen The Chemistry of Organometallic Compounds H. C= Clark Topics i n Organic Chemistry J.P.Kutney D. E. McGreer R.E.I. Pincock. Seminar i n Chemistry W.A, Bryce Related Studies: Modern Physics M. Bloom Programming and Numerical Algorithms . - ' H. Dempster Topics i n Chemical Metallurgy A.M.Armstrong E. Peters PUBLICATIONS N. B a r t l e t t and P.R. Rao Xenon Hydroxide - an Experimental Hazard Science (Washington), 139, 506, 1963. N. B a r t l e t t and P.R. Rao New Fluorides of Palladium: Palladium (II) Hexafluoropalladate (IV), P d 2 + ( P d F 6 ) 2 ~ , and Related Compounds and Palladium T e t r a f l u o r i d e Proc. Chem. Soc. 393, 1964. N. B a r t l e t t and P.R. Rao Iridium Pentafluoride Chem. Comm. 252, 1965. J.H. Holloway, P.R. Rao and N. B a r t l e t t Quinquivalent Rhodium Compounds: RI1F5 and CsRhF6 Chem. Comm. 306, 1965. NEW FLUORIDES OF THE NOBLE METALS by RAMESH PATHUR RAO B . S c , U n i v e r s i t y of Madras, I n d i a , 1958 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n the Department of Chemistry We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA September, 1965 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1 a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r a g r e e t h a t p e r -m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e Head o f my Department o r by h i s r e p r e s e n t a t i v e s * I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i -c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f Chemi stry- The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada Date September 8. 1965. i i ABSTRACT The compound p r e v i o u s l y i d e n t i f i e d as p a l l a d i u m t r i f l u o r i d e and as such accepted as the o n l y unambiguous t e r v a l e n t p a l l a d i u m compound, has been shown to be the mixed valence compound Pd^+[jPdFg"3 ~. T h i s has r e s o l v e d d i f f i c u l t i e s a s s o c i a t e d with the d e s c r i p t i o n of PdF3 i n terms of c r y s t a l f i e l d theory. The s y n t h e s i s of a new s e r i e s of compounds of ge n e r a l formula Pd^ +[MFg~]^~, isomorphous with Pd^ +QPdFg~)^ and mag-n e t i c a l l y s i m i l a r to the l a t t e r has been achieved. The o x i -d a t i o n s t a t e of p a l l a d i u m e x c i t e d by bromine t r i f l u o r i d e has been shown to be +4 when good f l u o r i d e i o n donors are a v a i l a b l e (i.e.. when the s o l u t i o n i s b a s i c ) and +2 when good f l u o r i d e i o n a c c e p t o r s are present i n s o l u t i o n ( i . e . i n a c i d c o n d i t i o n s ) . Reasons f o r the i n s t a b i l i t y of Pd(III) i n a f l u o r i n e l i g a n d environment are d i s c u s s e d . A n t i f e r r o m a g n e t i c o r d e r i n g has been observed i n p a l l a d i u m d i f l u o r i d e . -This has accounted f o r the low value of the room temperature magnetic moment of the compound. A l e s s t e d i o u s s y n t h e s i s of p a l l a d i u m d i f l u o r i d e has been accomplished by the p y r o l y s i s of the new p a l l a d i u m ( I I ) hexafluorogermanate(IV), at temperatures above 350°. A t e t r a f l u o r i d e of p a l l a d i u m has been prepared f o r the f i r s t time. I t i s the h i g h e s t valence b i n a r y p a l l a d i u m f l u o r i d e now known. I t has a body ce n t e r e d t e t r a g o n a l l a t t i c e and i s i s o s t r u c t u r a l with uranium and thorium t e t r a c h l o r i d e s . The adduct of p a l l a d i u m t e t r a f l u o r i d e with bromine t r i f l u o r i d e , i i i (BrF^) 2PCIF4, has been prepared and was found to be isomorphic with the c o r r e s p o n d i n g p l a t i n u m compound. The magnetic s u s c e p t i b i l i t y of g o l d t r i f l u o r i d e has been r e i n v e s t i g a t e d . A n a l y t i c a l l y pure AuFg has been shown to be g diamagnetic. T h i s has unambiguously assi g n e d a low s p i n d c o n f i g u r a t i o n f o r Au(III) i n g o l d t r i f l u o r i d e . F l u o r o a u r a t e s ( I I I ) of sodium, potassium, n i t r o s y l , rubidium and caesium have been found to be diamagnetic. The s a l t s with the e x c e p t i o n of CsAuF^ proved to be isomorphous. A l s o NOAUF4 has been found to be isomorphous with N0BrF4. The e x i s t e n c e of a t e t r a p o s i t i v e s t a t e of g o l d has been i n d i c a t e d . Gold t e t r a f l u o r i d e i s a pale yellow, h i g h l y r e a c t i v e s o l i d . T h i s f i r s t paramagnetic compound o f g o l d i s amorphous to x - r a y s . The 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 of rhodium has been e s t a b l i s h e d . Rhodium p e n t a f l u o r i d e i s a deep red s o l i d , m.p. 95.5°, and i s h i g h l y r e a c t i v e . I t r e a c t s with carbon t e t r a c h l o r i d e , c h l o r i n e monofluoride being among the products. I t i s s t r u c t u r a l l y s i m i l a r to ruthenium p e n t a f l u o r i d e , but has a s m a l l e r molecular volume. A hexafluororhodate(V) has been prepared f o r the f i r s t time by r e a c t i n g rhodium p e n t a f l u o r i d e with s t o i c h i o m e t r i c amount of caesium f l u o r i d e i n i o d i n e penta-f l u o r i d e . I t i s s t r u c t u r a l l y s i m i l a r to the other caesium h e x a f l u o r o m e t a l l a t e s ( V ) of the noble metals. The h i t h e r t o unknown i r i d i u m p e n t a f l u o r i d e has been e s t a b l i s h e d and i t s i d e n t i t y / with the p r e v i o u s l y known i r i d i u m i v t e t r a f l u o r i d e has been r e v e a l e d . I r i d i u m p e n t a f l u o r i d e i s s t r u c t u r a l l y s i m i l a r to the other noble metal p e n t a f l u o r i d e s , and i s almost i s o d i m e n s i o n a l with ruthenium p e n t a f l u o r i d e . I t has magnetic p r o p e r t i e s t y p i c a l of a t h i r d t r a n s i t i o n s e r i e s 4 d e l e c t r o n i c c o n f i g u r a t i o n i n an o c t a h e d r a l or near o c t a h e d r a l environment. I t i s suggested that i n both rhodium and i r i d i u m p e n t a f l u o r i d e the s t r u c t u r a l u n i t i s a f l u o r i n e b r i d g e d tetramer as i n ruthenium p e n t a f l u o r i d e . V ACKNOWLEDGEMENTS I would l i k e to thank P r o f e s s o r N e i l B a r t l e t t f o r h i s guidance throughout t h i s work. I have been aided c o n s i d e r -a b l y on the p r a c t i c a l s i d e by the s t a f f of the Chemistry Workshop. In p a r t i c u l a r , I wish to thank Mr. Emil Matter f o r the apparatus which he has c o n s t r u c t e d f o r me and f o r the many improvements which he has suggested i n my plans f o r equipment. I wish a l s o to express my g r a t i t u d e to the N a t i o n a l Research C o u n c i l of Canada f o r f i n a n c i a l support, i n the form of a N a t i o n a l Research C o u n c i l S c h o l a r s h i p , and the U n i v e r s i t y of B r i t i s h Columbia f o r the p r o v i s i o n of f a c i l i t i e s to c a r r y out my r e s e a r c h . I am a l s o g r a t e f u l to Miss Dayle M a r t e l f o r the t y p i n g of a somewhat i l l e g i b l e manuscript. v i TABLE OF CONTENTS Page SECTION I GENERAL INTRODUCTION 1 SECTION II EXPERIMENTAL CHAPTER 1: General A n a l y t i c a l Techniques 12 CHAPTER 2: General P h y s i c a l Techniques 16 CHAPTER 3: General P r e p a r a t i v e Techniques ..J.. 20 CHAPTER 4: D e t a i l e d Experimental Work A. MISCELLANEOUS REAGENTS . 29 B. PALLADIUM FLUORIDES (1) P a l l a d i u m t r i f l u o r i d e - b r o m i n e t r i f l u o r i d e adduct, B r F 3 . P d F 3 : (a) P r e p a r a t i o n 31 (b) Magnetic s u s c e p t i b i l i t y data 31 (2) P a l l a d i u m ( I I ) h e x a f l u o r o p a l l a d a t e ( I V ) , P d 2 + C P d F 6 - ] 2 -(a) P r e p a r a t i o n 32 (b) Magnetic s u s c e p t i b i l i t y data 32 (c) I n f r a r e d spectrum 33 (d) D i f f u s e r e f l e c t e n c e spectrum 33 (3) P a l l a d i u m ( I I ) h e x a f l u o r o p l a t i n a t e ( I V ) , P d 2 + C P t F 6 l 2 -(a) P r e p a r a t i o n 33 (b) General p r o p e r t i e s . 34 v i i (c) X-ray powder data 34 (d) Magnetic s u s c e p t i b i l i t y data 37 (e) I n f r a r e d spectrum 37 (4) P a l l a d i u m ( I I ) hexafluorogermanate(IV), P d 2 + C G e F 6 l 2 " (a) P r e p a r a t i o n 38 (b) General p r o p e r t i e s 38 (c) X-ray powder data < 38 (d) Magnetic s u s c e p t i b i l i t y data 39 (e) I n f r a r e d spectrum 40 (5) P a l l a d i u m ( I I ) h e x a f l u o r o s t a n n a t e ( I V ) , 2+_ -.2-Pd £SnF 6J (a) P r e p a r a t i o n 40 (b) General p r o p e r t i e s ; 41 (c) X-ray powder data 41 (d) Magnetic s u s c e p t i b i l i t y data 42 (6) P a l l a d i u m d i f l u o r i d e , PdF2 (a) P r e p a r a t i o n employing selenium t e t r a -f l u o r i d e 42 (b) P r e p a r a t i o n by p y r o l y s i s of p a l l a d i u m (II) hexafluorogermanate(IV) 43 (c) General p r o p e r t i e s . 43 (d) Magnetic s u s c e p t i b i l i t y data 43 (7) P a l l a d i u m T e t r a f l u o r i d e , PdF 4 2+ 2-(a) P r e p a r a t i o n from Pd £PdF^) 44 (b) P r e p a r a t i o n from PdF2 45 v i i i (c) P r e p a r a t i o n employing OF2 45 2+ 2 -(d) P r e p a r a t i o n from Pd [_MFQ] s a l t s . . 45 (e) General p r o p e r t i e s 45 (f) P r e p a r a t i o n of (BrF3>2PdF4 4 5 (g) X-ray powder data f o r PdF 4 46 C. GOLD FLUORIDES (1) Gold T r i f l u o r i d e (a) P r e p a r a t i o n 48 (b) General p r o p e r t i e s 48 (c) Magnetic p r o p e r t i e s 48 (2) F l u o r o a u r a t e s ( I I I ) , A +QAuF4) ~ (a) P r e p a r a t i o n 48 (b) General p r o p e r t i e s 49 (c) X-ray powder data 49 (3) Gold t e t r a f l u o r i d e , AuF 4 (a) F l u o r i n a t i o n of gold t r i f l u o r i d e .... 57 (b) F l u o r i n a t i o n of an e l e c t r i c a l l y heated g o l d wire 57 (c) F l u o r i n a t i o n of i n d u c t i o n heated gold powder 57 (d) General p r o p e r t i e s of AuF 4 58 (e) X-ray powder data f o r AuF 4 58 (f) The magnetic p r o p e r t i e s of AuF 4 58 (4) F l u o r o a u r a t e s ( I V ) Attempted p r e p a r a t i o n 58 i x D. RHODIUM FLUORIDES (1) Rhodium Pentaf l u o r i d e , RI1F5 (a) P r e p a r a t i o n 59 (b) Other p r e p a r a t i v e methods 59 (c) General p r o p e r t i e s 59 (d) Magnetic s u s c e p t i b i l i t y data 59 (e) X-ray powder data 60 (f) I n f r a r e d spectrum . 62a (2) Caesium H e x a f l u o r o r h o d a t e ( V ) , CsRhFg (a) P r e p a r a t i o n 62a (b) General p r o p e r t i e s 62 (c) X-ray powder data •••• 62 E. IRIDIUM FLUORIDES (1) I r i d i u m P e n t a f l u o r i d e , IrF$ (a) P r e p a r a t i o n from i r i d i u m metal 63 (b) P r e p a r a t i o n by the r e d u c t i o n of i r i d i u m h e x a f l u o r i d e w i t h powdered g l a s s 63 (c) General p r o p e r t i e s 63 (d) Magnetic s u s c e p t i b i l i t y data 63 (e) X-ray powder data 64 (f) I n f r a r e d spectrum 66 SECTION I I I DISCUSSION CHAPTER 1: P a l l a d i u m D i f l u o r i d e 67 CHAPTER 2: P a l l a d i u m T r i f l u o r i d e and R e l a t e d Compounds 71 X CHAPTER 3: Gold T r i f l u o r i d e and i t s S a l t s 80 CHAPTER 4: The T e t r a f l u o r i d e s of P a l l a d i u m and Gold . 82 CHAPTER 5: The P e n t a f l u o r i d e s of Rhodium and I r i d i u m and Related•Compounds 89 BIBLIOGRAPHY 99 APPENDICES I A program f o r the d e t e r m i n a t i o n of the Bragg angle, i n t e r p l a n a r s p a c i n g D, / 2 1/D and Nelson R i l e y E x t r a p o l a t i o n F u n c t i o n . . . •••• 1 0 6 II A program f o r l e a s t square approxima-t i o n of magnetic s u s c e p t i b i l i t y data... 110 I I I A program f o r the c a l c u l a t i o n of 1/D n k l f o r the u n i t c e l l parameters 116 x i LIST OF TABLES Page TABLE I Molar s u s c e p t i b i l i t y data f o r P d F 3 . B r F 3 32 TABLE II Molar s u s c e p t i b i l i t y data f o r Pd 2 +[PdF£] 2 ~ ... 33 TABLE I I I C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r P d 2 + Q P t F 6 l 2 ~ 35 TABLE IV Molar s u s c e p t i b i l i t y data f o r P d 2 + [ P t F g l 2 " ... 37 TABLE V C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r P d 2 + £ G e F 6 l 2 " 39 TABLE VI Molar s u s c e p t i b i l i t y data f o r Pd2+QGeFg'] 2 ~ ... 40 TABLE VII C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r P d 2 + [ S n F 6 T 2 ~ 41 TABLE V I I I Molar s u s c e p t i b i l i t y data f o r P d 2 + [ S n F g l 2 ~ ... 42 TABLE IX Molar s u s c e p t i b i l i t y data f o r PdF2 44 TABLE X C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r PdF4 46 TABLE XI The c e l l parameters f o r A + A u F 4 ~ s a l t s 50 TABLE XII C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r NaAuF4 . . . 50 TABLE XIII C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r KAuF 4 52 TABLE XIV C a l c u l a t e d and observed X-ray d i f f r a c t i o n data f o r NOAuF 4 54 TABLE XV C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r RbAuF 4 55 TABLE XVI Molar s u s c e p t i b i l i t y data f o r RhF 5 60 x i i Page TABLE XVII C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r RhF 5 61 TABLE XVIII Molar s u s c e p t i b i l i t y data f o r I r F 5 64 TABLE XIX C a l c u l a t e d and observed x-ray d i f f r a c t i o n data f o r I r F 5 64 TABLE XX S t r u c t u r a l data f o r some d i - and t r i - f l u o r i d e s 72 TABLE XXI U n i t c e l l parameters f o r Pd [MFQ\ s a l t s ... 74 TABLE XXII I n f r a r e d s p e c t r a of some P d 2 + [ M F 6 " ] 2 ~ and A2MF6 compounds 76 TABLE XXIII Known p e n t a f l u o r i d e s of the second and t h i r d t r a n s i t i o n s e r i e s metals 93 TABLE XXIV E s t a b l i s h e d b i n a r y f l u o r i d e s of the platinum metals 98 x i i i LIST OF FIGURES Page FIGURE 1. A gen e r a l purpose f l u o r i n e l i n e 21-22 FIGURE 2. Apparatus f o r r e a c t i o n with f l u o r o -s o l v e n t s 27 FIGURE 3. T e m p e r a t u r e - s u s c e p t i b i l i t y r e l a t i o n f o r PdF 2 69 FIGURE 4. Curie-Weiss p l o t s f o r the P d 2 + [ M F 6 1 2 ~ s a l t s 75 FIGURE 5. I n t e r r e l a t i o n s h i p s of p a l l a d i u m f l u o r i d e s . 88 FIGURE 6. S t r u c t u r e types f o r AMFg s a l t s 94 FIGURE 7. I n t e r r e l a t i o n s h i p s of rhodium f l u o r i d e s .. 96 FIGURE 8. I n t e r r e l a t i o n s h i p s of i r i d i u m f l u o r i d e s .. 97 x i v LIST OF PLATES F o l l o w i n g Page PLATE 1. The p a l l a d i u m ( I I ) h e x a f l u o r o m e t a l l a t e s ( I V ) . 74 PLATE 2. P a l l a d i u m t e t r a f l u o r i d e and p a l l a d i u m hexaf l u o r o p a l l a d a t e (IV) 84 PLATE 3. T e t r a f l u o r i d e s of palladium, platinum and t i n 85 PLATE 4. P e n t a f l u o r i d e s of ruthenium, rhodium, i r i d i u m and platinum 91 SECTION I GENERAL INTRODUCTION 1 Although f l u o r i n e was f i r s t generated by Moissan i n 1886, few workers s t u d i e d the chemistry of the element p r i o r to World War I I . Before that time work with the element was d i f f i c u l t and hazardous - indeed, much of the r e c e n t growth i n the f i e l d must be a t t r i b u t e d to the improvements i n the technology of f l u o r i n e and f l u o r i n e h a n d l i n g . A major s t i m u l u s to t h i s improve-ment was the i n t e r e s t i n uranium h e x a f l u o r i d e as a route to the s e p a r a t i o n of uranium i s o t o p e s . An a p p r a i s a l of uranium hexa-f l u o r i d e and f l u o r i n e became part of the U. S. Army Manhattan D i s t r i c t , known as the "Manhattan D i s t r i c t " i n September 1942. The developments which f o l l o w e d , q u i c k l y l e d to r e l i a b l e and simple g e n e r a t i o n and h a n d l i n g techniques f o r f l u o r i n e gas. I t i s l a r g e l y a consequence of t h i s , t h a t r e l i a b l e f l u o r i n e genera-t o r s and s u p p l i e s of compressed f l u o r i n e are now r e a d i l y a v a i l a b l e f o r both i n d u s t r i a l and r e s e a r c h purposes. In the past decade numerous new s y n t h e t i c procedures have been d e s c r i b e d and techniques f o r h a n d l i n g h i g h l y r e a c t i v e f l u o r -i d e s have much improved. H i g h l i g h t s i n c l u d e the i d e n t i f i c a t i o n by Weinstock and h i s coworkers at the Argonne N a t i o n a l Laboratory, of the v o l a t i l e f l u o r i d e of osmium, long i d e n t i f i e d as osmium o c t a f l u o r i d e , as a h e x a f l u o r i d e . ^ The same workers were a l s o r e s p o n s i b l e f o r the p r e p a r a t i o n of the h e x a f l u o r i d e s of platinum, technicium, ruthenium and rhodium . Platinum h e x a f l u o r i d e has proved to be the most powerful o x i d i s e r known hitherto.'6,7 I n t e r e s t i n the noble metal f l u o r i d e s dates back to Moissan 8 9 who r e p o r t e d a d i f l u o r i d e and a t e t r a f l u o r i d e of platinum. Ruff, however, was the p r i n c i p a l c o n t r i b u t o r to the f l u o r i n e chemistry of the noble metals. H i s work"^ l a i d a f o u n d a t i o n f o r l a t e r workers to b u i l d on. 2 The o n l y known u n i v a l e n t noble metal f l u o r i d e i s that of s i l v e r , which i s best made by the decomposition of s i l v e r f l u o r o -borate at 2 0 0 ° . 1 1 The absence of a monofluoride of gold has been 12 a t t r i b u t e d to i t s thermodynamic i n s t a b i l i t y . 13 D i f l u o r i d e s have been prepared o n l y f o r s i l v e r and p a l l a -14 dium. Impure p a l l a d o u s f l u o r i d e was prepared by Ruff and Ascher by r e d u c t i o n of the t r i f l u o r i d e with a v a r i e t y of r e d u c i n g agents i n c l u d i n g hydrogen, i o d i n e , s u l f u r d i o x i d e and p a l l a d i u m metal i t s e l f . B a r t l e t t and Hepworth 1^ made the d i f l u o r i d e i n high pur-i t y by r e d u c i n g the t r i f l u o r i d e with selenium t e t r a f l u o r i d e and e s t a b l i s h e d i t as the f i r s t known paramagnetic Pd(II) compound. I t i s p o s s i b l e t h a t o t h e r noble metal d i f l u o r i d e s may be prepar-a b l e , but with the p a u c i t y of thermodynamic data a v a i l a b l e , i t i s not p o s s i b l e to exclude the d i s p r o p o r t i o n a t i o n r e a c t i o n : MF2 — * M + MF X. The i n a b i l i t y to c o n f i r m Moissan and R u f f ' s c l a i m s f o r p l a t i -num d i f l u o r i d e has been a t t r i b u t e d to t h i s p o s s i b i l i t y . ^ 1 The o n l y known d i v a l e n t noble metal complex f l u o r i d e i s t h a t of palladium, C s P d F 3 , prepared by Bartlett.^®>22 T r i f l u o r i d e s have been prepared f o r a l l of the noble metals except osmium, platinum and s i l v e r . Ruthenium t r i f l u o r i d e was 17 r e p o r t e d by Aynsley, Peacock and Robinson as the product of r e d u c t i o n of ruthenium p e n t a f l u o r i d e by i o d i n e at 150°. Rhodium 18 t r i f l u o r i d e was formed by l i m i t e d f l u o r i n a t i o n of the metal at o 19 400-600 . Peacock prepared K3RI1F6 by the a c t i o n of KHF 2 on K 3 R h ( N 0 2 ) 6 -3 P a l l a d i u m t r i f l u o r i d e , a black s o l i d , h y d r o l i z a b l e by water, o 2 0 was o b t a i n e d by the f l u o r i n a t i o n of the metal at 500 or by t r e a t i n g the i o d i d e with bromine t r i f l u o r i d e and h e a t i n g the pro-duct of t h i s r e a c t i o n at 1 8 0 ° . 2 1 F u r t h e r , Sharpe has shown that p a l l a d i u m bromide i n bromine t r i f l u o r i d e y i e l d s BrF3.PdF3, which i s decomposed to the t r i f l u o r i d e . A l l attempts, to prepare com-plex f l u o r i d e s of Pd(III) however, have been u n s u c c e s s f u l . Instead, h e x a f l u o r o p a l l a d a t e s ( I V ) proved to be the products of such r e a c -22 23 t i o n s i n bromine t r i f l u o r i d e . ' I r i d i u m t r i f l u o r i d e was p r e p a r e d 2 4 1 3 by the r e d u c t i o n of the h e x a f l u o r i d e . E f f o r t s to prepare platinum and osmium t r i f l u o r i d e s , have so f a r been u n s u c c e s s f u l . Evidence f o r the e x i s t e n c e of a f l u o r i d e of g o l d was noted 25 by Moissan, who heated g o l d wire i n f l u o r i n e at d u l l r e d heat and observed the f o r m a t i o n of a hygroscopic c r u s t of orange powder on the metal. However, g o l d t r i f l u o r i d e was f i r s t p re-26 pared i n a n a l y t i c a l p u r i t y by Sharpe, by treatment of gold powder with 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 s had been r e p o r t e d f o r most of the noble metals before the present work was undertaken. Exc e p t i o n s were those of p a l l a d i u m , s i l v e r and g o l d . A l l of the t e t r a f l u o r i d e s were assigned high m e l t i n g and b o i l i n g p o i n t s with the c u r i o u s e x c e p t i o n of i r i d i u m , a which p h y s i c a l l y , more c l o s e l y resembled a penta-24b f l u o r i d e or an oxide t e t r a f l u o r i d e . Even though recent work had confirmed the e a r l i e r c o n c l u s i o n , the f o r m u l a t i o n was, however, based s o l e l y upon a n a l y t i c a l data. T h i s anomaly, and i t s import-ant s t r u c t u r a l i m p l i c a t i o n s , c l e a r l y r e q u i r e d f u r t h e r support from 4 magnetic and s t r u c t u r a l data. There was, h i t h e r t o no r e p o r t e d s u c c e s s f u l e f f o r t to prepare the t e t r a f l u o r i d e s of p a l l a d i u m or g o l d . A l l of the noble metals other than s i l v e r and g o l d form 2 — LMF6-^ s a l t s . The yellow h y g r o s c o p i c complexes I^RhFg, 27 Rb2RhF6 and Cs 2RhFg were prepared by Weise and Klemm by the a c t i o n of f l u o r i n e at 320°, on the complex c h l o r i d e s of approp-r i a t e s t o i c h i o m e t r y , such as K2RI1CI5. However, they are most 21 c o n v e n i e n t l y made by Sharpe's route which employs bromine t r i f l u o r i d e both as o x i d i s i n g agent and s o l v e n t . P a l l a d i u m 23 complexes of A2MF6 type are prepared by s i m i l a r methods. Such 28 33 34 complexes are a l s o known f o r ruthenium, osmium, i r i d i u m ' 21 23 and platinum. ' The s a l t s of the l a t t e r metals, however, are k i n e t i c a l l y s t a b l e i n water u n l i k e the rhodium and p a l l a d i u m 2 — cases. Although p r e v i o u s attempts to prepare g o l d L.MF61 s a l t s had f a i l e d , i t n e v e r t h e l e s s appears probable that by use of a more powerful f l u o r i n a t i n g agent and c a t i o n s of low p o l a r i z i n g power, t h i s i o n c o u l d be s t a b i l i z e d . P e n t a f l u o r i d e s are known f o r r u t h e n i u m , o s m i u m ^ ^ a and 31 platinum. Ruthenium p e n t a f l u o r i d e i s c o n v e n i e n t l y made by the a c t i o n of bromine t r i f l u o r i d e on the metal. Hargreaves 30a and Peacock prepared osmium p e n t a f l u o r i d e by the r e a c t i o n of tungsten c a r b o n y l with an excess of osmium h e x a f l u o r i d e and by o t h e r methods, and have e s t a b l i s h e d i t s i d e n t i t y with the p r e -*3 Ci V \ v i o u s l y r e p o r t e d h e x a f l u o r i d e . Platinum p e n t a f l u o r i d e may be made i n s m a l l y i e l d as r e p o r t e d by B a r t l e t t and Lohmann, by the 31 medium temperature f l u o r i n a t i o n of platinum d i c h l o r i d e . In 5 view of the e x i s t e n c e of PtF§ and O S F 5 the absence of XrF5 was a l l the more p u z z l i n g . Indeed, i t d i d appear probable at the o u t s e t of t h i s work, t h a t the t e t r a f l u o r i d e c o u l d be a penta-f l u o r i d e . Furthermore, the p o s s i b i l i t y of rhodium p e n t a f l u o r i d e remained to be e x p l o r e d . The absence of t h i s f l u o r i d e was d i f -f i c u l t to account f o r i n view of the e x i s t e n c e of a t e t r a f l u o r i d e and a h e x a f l u o r i d e . I t was of course d e s i r a b l e to pursue the syn-t h e s i s of p a l l a d i u m p e n t a f l u o r i d e . 32 Complex f l u o r i d e s of q u i n q u i v a l e n t ruthenium, osmium, i r i d i u m ' and platinum had been prepared, those of gold, rhodium, p a l l a d i u m and s i l v e r remained to be s y n t h e s i z e d . Apart from the d i s c o v e r i e s of Weinstock and h i s coworkers mentioned e a r l i e r , the o n l y other hexavalent noble metal f l u o r i d e 29b to be r e p o r t e d i s the oxide t e t r a f l u o r i d e of ruthenium, de-s c r i b e d by Holloway and Peacock. So f a r , d e s p i t e attempts at 5 i t s p r e p a r a t i o n , p a l l a d i u m h e x a f l u o r i d e has not been made, nor has g o l d h e x a f l u o r i d e . The o n l y h e p t a v a l e n t f l u o r i d e to be d e s c r i b e d i s osmium 35 oxide p e n t a f l u o r i d e . Octavalence i s r e p r e s e n t e d i n osmium t r i o x i d e d i f l u o r i d e and i t s s a l t s . A u s e f u l b a s i s f o r the comparison of the noble metal f l u o r -i d e s i s i n terms of molecular and c r y s t a l s t r u c t u r e . In p a r t i c u l a r a comparison of l i g a n d geometries about the v a r i o u s c e n t r a l noble metal atoms, i s of importance. Of the noble metal d i f l u o r i d e s , 37 the s t r u c t u r e of PdF 2 i s the o n l y one known with c e r t a i n t y . I t has the r u t i l e s t r u c t u r e with an almost r e g u l a r arrangement of f l u o r i n e l i g a n d s about the p a l l a d i u m atom (4F at 2.15, 2F at 2.17 % ) . T h i s i s c o n s i s t e n t i n terms of Ligand F i e l d Theory, g with the h i g h s p i n d c o n f i g u r a t i o n of the Pd(II) i n t h i s com-pound. In diamagnetic compounds of P d ( I I ) , the c o o r d i n a t i o n i s g e n e r a l l y g r o s s l y d i s t o r t e d from o c t a h e d r a l and u s u a l l y a p p r o x i -mates to square p l a n a r . There i s no unambiguous evidence f o r s i l v e r d i f l u o r i d e being a Ag(II) f l u o r i d e . The compound i s not p r o p e r l y c h a r a c t e r i z e d s t r u c t u r a l l y and the l i m i t e d magnetic data has no s t r u c t u r a l l y d i a g n o s t i c v a l u e . The dark brown d i f l u o r i d e c o u l d be the complex f l u o r i d e , s i l v e r ( I ) f l u o r o a r g e n t a t e ( I I I ) , Ag +AgF 4~. A d e t a i l e d magnetic study and s t r u c t u r a l study of t h i s compound i s t h e r e f o r e d e s i r a b l e . The t r i f l u o r i d e s of ruthenium, rhodium, p a l l a d i u m and i r i d i u m have been r e p o r t e d to c r y s t a l l i z e with a b i m o l e c u l a r rhombohedral - 38 39 unxt c e l l of space group R3C. Neutron d i f f r a c t i o n s t u d i e s are i n accord with t h i s o b s e r v a t i o n . The f l u o r i n e l i g a n d arrangement i s hexagonal close-packed i n RhF 3, PdF 3 and I r F 3 . For RuFg, a d i s t o r t i o n from hexagonal c l o s e - p a c k i n g i s observed. RuF 3, and to a s m a l l e r extent I r F 3 , both show v a r i a b i l i t y i n t h e i r u n i t c e l l dimensions, which has been a t t r i b u t e d to v a r i a t i o n i n s t o i c h i o -17 metry. The o r i g i n a l method of p r e p a r a t i o n of RuFg was from p e n t a f l u o r i d e of d o u b t f u l p u r i t y , and i t i s p o s s i b l e t h a t the t r i f l u o r i d e may be produced i n s o l i d s o l u t i o n with an o x y f l u o r i d e , e.g. RuOF 2. To r e s o l v e these matters, t h i s t r i f l u o r i d e i s t h e r e -f o r e c e r t a i n l y worthy of magnetic i n v e s t i g a t i o n as w e l l as s t r u c -t u r a l i n v e s t i g a t i o n . 7 P r e l i m i n a r y i n v e s t i g a t i o n of the magnetic p r o p e r t i e s of 40 , o PdF3 gave a magnetic moment value = 2.05 B.M., at 20 which 40 was i n t e r p r e t e d by Nyholm and Sharpe as i n d i c a t i n g a low s p i n 6 1 e l e c t r o n c o n f i g u r a t i o n 4d^ , d r f o r the o c t a h e d r a l l y c o o r d i n a t e d P d ( I I I ) atom f o r which the Pd-F d i s t a n c e s are a l l r e p o r t e d to be o 2.04 A. Ligand F i e l d Theory, however p r e d i c t s a d i s t o r t e d e n v i r o n -ment f o r an i o n with such a c o n f i g u r a t i o n . 41 Gold t r i f l u o r i d e i s hexagonal and i s a p p a r e n t l y not i s o -s t r u c t u r a l with any known t r i f l u o r i d e s . I t i s suggested that the sudden i n c r e a s e i n molecular volume of AuFg compared with other t r i f l u o r i d e s a r i s e s from a lower l i g a n d c o o r d i n a t i o n than i s normal elsewhere. The magnetic p r o p e r t i e s of AuF 3 were f i r s t i n v e s t i g a t e d by Nyholm and S h a r p e . 4 0 T h e i r study i n d i c a t e d t hat g o l d t r i f l u o r i d e was paramagnetic ( = 0.5 B.M.), and as such r e p r e s e n t e d the f i r s t paramagnetic Au(III) compound. A magnetic moment as low as t h i s c o u l d be due to paramagnetic i m p u r i t y however, and no r e l i a b l e s t r u c t u r a l s i g n i f i c a n c e was j u s t i f i a b l e without a f u l l e r magnetic study on m a t e r i a l of h i g h , p u r i t y . D i a -magnetism would, of course, suggest a square planar or t e t r a g o n a l s p l i t t i n g of the 5d o r b i t a l s ; i n which the h i g h e s t energy o r b i t a l would be empty. On the o t h e r hand, paramagnetic Au(III) would o n l y be l i k e l y to occur with a near o c t a h e d r a l or o c t a h e d r a l environment. Diamagnetic complexes of t e r v a l e n t noble metal f l u o r i d e s of 42 the form AMF 4 are known o n l y i n the case of s i l v e r and go l d . 43 S t r u c t u r a l evidence f o r the potassium s a l t of g o l d i n d i c a t e s 8 t h a t they may have a square planar arrangement of f l u o r i n e atoms about the noble metal atom. S t r u c t u r a l s t u d i e s on the t e t r a f l u o r i d e s of noble metals are sparse. I t i s probable t h a t P t F 4 has a s l i g h t l y d i s t o r t e d ' 44 U C I 4 s t r u c t u r e with e i g h t c o o r d i n a t i o n i n f l u o r i n e (4 c l o s e 31 f l u o r i n e l i g a n d and 4 d i s t a n t ) . Rhodium t e t r a f l u o r i d e prepared 31 by Sharpe's method i s not isomorphous with PtF^. I t i s of course p o s s i b l e t h a t the s t r u c t u r a l v a r i a t i o n may be accounted f o r by v a r i a t i o n i n c o o r d i n a t i o n number from compound to compound. However, no f i r m g e n e r a l statements co n c e r n i n g the s t r u c t u r a l r e l a t i o n s h i p s of the t e t r a f l u o r i d e s c o u l d be made without f u r t h e r s t r u c t u r a l data on the t e t r a f l u o r i d e s . The s y n t h e s i s and s t r u c t u r a l chemistry of s e v e r a l t r a n s i t i o n metal p e n t a f l u o r i d e s have been i n v e s t i g a t e d by Peacock and h i s coworkers. They r e p o r t t h a t , of those of the noble metals, 45 ruthenium and osmium p e n t a f l u o r i d e s are isomorphous. The s t r u c t u r a l u n i t i n RuF^ and presumably i n O S F 5 i s the tetramer M 4 F 2 0• The s t r u c t u r e of ruthenium p e n t a f l u o r i d e i s based on a hexagonal close-packed arrangement of f l u o r i n e atoms with a tetramer l i n k e d by n o n - l i n e a r b r i d g i n g f l u o r i n e atoms. I t i s of i n t e r e s t to determine the p o s s i b i l i t y of platinum p e n t a f l u o r -i d e being isomorphous with these :compounds. I t i s a l s o c l e a r t h a t the demonstration of isomorphism of i r i d i u m t e t r a f l u o r i d e w i t h these p e n t a f l u o r i d e s c o u l d be a c o n v i n c i n g argument f o r i t s r e i d e n t i f i c a t i o n as a p e n t a f l u o r i d e . The s t r u c t u r e s of com-32 46 p l e x h e x a f l u o r o r u t h e n a t e s ( V ) , hexafluoroosmates(V), hexa-46 f l u o r o i r i d a t e s ( V ) and h e x a f l u o r o p l a t i n a t e s ( V ) ^ 1 have been r e p o r t e d . 9 The v o l a t i l e noble metal h e x a f l u o r i d e s have i n the vapour 1 47 phase the r e g u l a r o c t a h e d r a l c o n f i g u r a t i o n . ' At low tempera-t u r e s , the u n i t c e l l i s orthorhombic. At higher temperatures a l l of the h e x a f l u o r i d e s undergo a phase t r a n s i t i o n to a l e s s dense body ce n t e r e d c u b i c m o d i f i c a t i o n . The t r a n s i t i o n occurs g e n e r a l -l y i n the neighbourhood of 0 ° . 4 ^ q The preceding review has presented a g e n e r a l c r i t i c a l a p p r a i s a l of s y n t h e t i c and c r y s t a l l o g r a p h i c work r e l a t i n g to the noble metal f l u o r i d e s . S e v e r a l f e a t u r e s appeared to be worthy of f u r t h e r i n v e s t i g a t i o n . I t w i l l have been noted that the o x i d a t i o n maximum f a l l s s t r i k i n g l y from ruthenium to s i l v e r , and from osmium to g o l d . Such a f a l l i s more pronounced i n the second t r a n s i t i o n s e r i e s than i n the t h i r d . The t r e n d i n o x i -d i s i n g p r o p e r t i e s of the h e x a f l u o r i d e s of the noble metals suggests t h a t p a l l a d i u m h e x a f l u o r i d e , i f i t can be made, must be l e s s s t a b l e than rhodium h e x a f l u o r i d e , which i s the l e a s t s t a b l e of the known h e x a f l u o r i d e s . Since the p o l a r i z i n g power 5 of g o l d i n g o l d h e x a f l u o r i d e (d-^g) w o u l d be g r e a t e r than that 4 of platinum h e x a f l u o r i d e ( d ^ g ) ' t n e f ° r m e r would be l e s s s t a b l e . N e v e r t h e l e s s , t h i s does not r u l e out the p o s s i b l e s y n t h e s i s of AuFg. The h i g h e s t known f l u o r i d e of p a l l a d i u m i s the t r i f l u o r i d e , w h i l e i t s group neighbour platinum even forms a h e x a f l u o r i d e . There i s no thermodynamic data to i n d i c a t e i n s t a b i l i t y of the t e t r a or p e n t a f l u o r i d e s of p a l l a d i u m . However, e f f o r t s to prepare p a l l a d i u m h e x a f l u o r i d e u s i n g r a p i d quenching techniques f a i l e d to y i e l d a n y t h i n g but the t r i f l u o r i d e . N e v e r t h e l e s s , the 10 I, ease with which platinum t e t r a f l u o r i d e i s prepared, g i v e s hope f o r at l e a s t a t e t r a f l u o r i d e of pal l a d i u m . At the o u t s e t the s y n t h e s i s of p a l l a d i u m t e t r a f l u o r i d e and go l d t e t r a f l u o r i d e are c a l l e d f o r . F a i l u r e to o b t a i n s i l v e r t r i f l u o r i d e i s i n accord with the powerful o x i d i s i n g nature of i t s d i f l u o r i d e , but i t may be pre p a r a b l e under p o w e r f u l l y o x i d i s i n g c o n d i t i o n s . The e x i s t e n c e of the t e r v a l e n t complex f l u o r i d e s g i v e s some eventual hope of t h i s . The p e n t a f l u o r i d e chemistry of the noble metals deserves f u r t h e r c o n s i d e r a t i o n . In view of the e x i s t e n c e of the hexa-f l u o r i d e s of rhodium and i r i d i u m , i t i s p u z z l i n g t h a t t h e i r p e n t a f l u o r i d e s cannot be made, e s p e c i a l l y s i n c e the p e n t a f l u o r -i d e s of the neighbouring elements ruthenium, rhenium, osmium and platinum are known. P e c u l i a r l y enough, s e v e r a l complexes of q u i n q u i v a l e n t i r i d i u m are known, but pr e v i o u s attempts to e s t a b l i s h the simple f l u o r i d e have been without success. As p o i n t e d out e a r l i e r , the p h y s i c a l and chemical p r o p e r t i e s g i v e n f o r the t e t r a f l u o r i d e resembled those of a p e n t a f l u o r i d e . I t t h e r e f o r e r e q u i r e d r e i n v e s t i g a t i o n . The s y n t h e s i s of rhodium and i r i d i u m p e n t a f l u o r i d e s not o n l y has chemical and s t r u c t u r a l s i g n i f i c a n c e , but the magnetic p r o p e r t i e s of such compounds are a l s o of i n t e r e s t s i n c e they 4 are r e p r e s e n t a t i v e of the d nonbonding e l e c t r o n i c systems of 4 the second and t h i r d t r a n s i t i o n s e r i e s . The d c o n f i g u r a t i o n can g i v e r i s e to 0, 2 or 4 unpaired e l e c t r o n s . The va l u e s of atomic magnetic moments o b t a i n e d from s u s c e p t i b i l i t y measure-ments on 4d and 5d compounds are g e n e r a l l y q u i t e s m a l l and they 11 do not correspond to the s p i n o n l y v a l u e s c h a r a c t e r i s t i c of the i r o n group. Furthermore, one c o u l d not a n t i c i p a t e the s t r u c t u r a l r e l a t i o n s h i p w i t h the other p e n t a f l u o r i d e s . T h e i r isomorphism or otherwise with the other noble metal f l u o r i d e s was of some th e o r -e t i c a l s i g n i f i c a n c e . New t r i f l u o r i d e s to be sought among the members of the p l a t i -num group are those of platinum and osmium. The s t r u c t u r e and magnetic p r o p e r t i e s of the t r i f l u o r i d e s of ruthenium and i r i d i u m need f u r t h e r i n v e s t i g a t i o n . I t i s p o s s i b l e that i n the case of elements p o s s e s s i n g more thermodynamically f a v o u r a b l e higher f l u o r i d e s , e.g. osmium, d i s p r o p o r t i o n a t i o n may be favoured: MF3 -—* MF4 + M. The s y n t h e s i s of a t r i f l u o r i d e of platinum i s a l s o of i n t e r e s t . T h i s compound c o u l d d i f f e r s t r u c t u r a l l y and m a g n e t i c a l l y from i t s p a l l a d i u m analogue. One of the i n t e r e s t i n g anomalies of the noble metal f l u o r i n e f i e l d at the o u t s e t was the p a l l a d i u m t r i f l u o r i d e problem, p r e v i o u s l y r e f e r r e d t o . The magnetic p r o p e r t i e s and the observed c r y s t a l s t r u c t u r e are not compatible i n terms of the Ligand F i e l d Theory. Hence the prob-lem of seeking an unambiguous s o l u t i o n to t h i s end was given prime c o n s i d e r a t i o n d u r i n g the present i n v e s t i g a t i o n . SECTION II EXPERIMENTAL 12 CHAPTER 1: General A n a l y t i c a l Techniques Standard a n a l y t i c a l methods were employed wherever p o s s i b l e 4-Q in, t h i s work. The methods given by Scott^° were being f o l l o w e d . E s t i m a t i o n of F l u o r i n e Q u a n t i t a t i v e d e t e r m i n a t i o n of f l u o r i n e i s g e n e r a l l y t e d i o u s but s e v e r a l s a t i s f a c t o r y methods are a v a i l a b l e . 5 0 a » b » c The two 51, 52 methods and t h e i r v a r i a n t s used i n t h i s work were p y r o h y d r o l y s i s and the W i l l a r d Winter d i s t i l l a t i o n . ^ O ften both approaches were used f o r the a n a l y s i s of one compound. P y r o h y d r o l y s i s has been used e x t e n s i v e l y i n the a n a l y s i s of i n v o l a t i l e f l u o r i d e s . The temperature r e q u i r e d f o r complete p y r o h y d r o l y s i s depended upon the nature of the compound. In a t y p i c a l a n a l y s i s , a s m a l l platinum boat was weighed i n a h o r i -z o n t a l weighing b o t t l e a f t e r r e d u c t i o n with hydrogen at 300°. A known weight of the f l u o r i d e sample (0.1 to 0.4 g) i n the boat was q u i c k l y t r a n s f e r r e d to the p y r o h y d r o l y s i s tube at room tempera-t u r e . Moist a i r was passed over the sample f o r f i v e minutes, and the furnace temperature and water temperature i n the steam gen-e r a t o r were-slowly r a i s e d . F i n a l l y steam was passed over the sample at 300° and the d i s t i l l a t e were passed i n t o 40 mis of water c o n t a i n e d i n a c o n i c a l f l a s k . The c a r r i e r gas was n i t r o g e n . The f l u o r i d e i o n c o n c e n t r a t i o n was estimated by t i t r a t i o n with standard sodium hydroxide s o l u t i o n 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 . U s u a l l y about 300 mis of d i s t i l l a t e were c o l l e c t e d , and h y d r o l y s i s waS continued u n t i l t here was no change i n t i t r e . 13 The v o l u m e t r i c e s t i m a t i o n was v e r i f i e d g r a v i m e t r i c a l l y . F l u o r i d e was determined as l e a d c h l o r o f l u o r i d e i n the u s u a l 54 way . The p u r i t y of the l e a d c h l o r o f l u o r i d e p r e c i p i t a t e i t s e l f was checked by c h l o r i d e a n a l y s i s as s i l v e r c h l o r i d e . T h i s v e r i -f i c a t i o n was needed, e s p e c i a l l y when W i l l a r d Winter d i s t i l l a t i o n with s u l f u r i c a c i d was used f o r the decomposition of the f l u o r i d e . The p o s s i b i l i t y of l e a d s u l f a t e being p r e c i p i t a t e d i n such cases was l i k e l y . The W i l l a r d Winter d i s t i l l a t i o n was p r e f e r r e d i n cases where p y r o h y d r o l y s i s f a i l e d because of incomplete.decomposition. In t h i s method, a weighed q u a n t i t y of the compound (0.1 - 0.4 g) was t r e a t e d with c o n c e n t r a t e d s u l f u r i c a c i d (40 mis) or p e r c h l o r i c a c i d and b o i l e d at 130 - 135°, the temperature being c o n t r o l l e d by the a d d i t i o n of water through a dropping f u n n e l . When about 300 mis of d i s t i l l a t e , c o n t a i n i n g the f l u o r i n e as h y d r o f l u o r i c and f l u o r o s i l i c i c a c i d s c o l l e c t e d , the d i s t i l l a t i o n was stopped. F l u o r i d e i n t h i s d i s t i l l a t e was determined as l e a d c h l o r o f l u o r i d e . The method s u f f e r s from the disadvantage t h a t o n l y one component ( c f . f l u o r i n e ) can be estimated at a time. Decomposition of the f l u o r i d e was a l s o e f f e c t e d by f u s i o n 21 with sodium carbonate. A weighed amount of the sample (0.2 -0.5 g) was covered with A.R. grade sodium carbonate (3 g ) , i n a platinum boat, t h i s being done i n a dry dox. The boat was heated to r e d heat. The f l u o r i d e was leached with water a f t e r d i g e s t i o n f o r one hour i n b o i l i n g water. Heavy metal, o x i d e s , i f p r e s ent, were removed by f i l t r a t i o n and f l u o r i d e i n the f i l -t r a t e was estimated as l e a d c h l o r o f l u o r i d e . 14 The sodium carbonate f u s i o n method was extremely u s e f u l f o r the more r e a d i l y h y d r o l i z a b l e f l u o r i d e s where decomposition i n the u s u a l h a n d l i n g procedures l e d to l o s s of f l u o r i n e . E s t i m a t i o n of Noble Metals F o l l o w i n g p y r o h y d r o l y s i s , the boat was l e f t w ith impure metal, oxide or hydrated o x i d e s of these metals. To reduce these, the apparatus was f l u s h e d with n i t r o g e n , and then with hydrogen. The r e d u c t i o n was c a r r i e d out at 350 - 400°. Excess hydrogen was burned at a s i l i c a o u t l e t to the combustion tube. P a l l a d i u m was best determined as i t s dimethyl glyoxime 55 complex, Pd(C 4Hy02N2)2 • A weighed amount of the compound, c o n t a i n i n g not more than 0.1 g of p a l l a d i u m i n 250 ml, was evaporated n e a r l y to dryness with c o n c e n t r a t e d h y d r o c h l o r i c a c i d to remove f l u o r i d e as hydrogen f l u o r i d e . The s o l u t i o n was d i l u t e d to 0.25 N i n HC1; then t r e a t e d with 1% s o l u t i o n of dimethyl glyoxime i n 95% a l c o h o l at room temperature. About 4 ml of the reagent was used f o r every 10 mg. of pa l l a d i u m . The s o l u t i o n was allowed to stand f o r 1 hr. The w e l l separated p r e c i p i t a t e was f i l t e r e d o f f on a Gooch c r u c i b l e . The orange yellow p r e c i p i t a t e of p a l l a d i u m dimethyl glyoxime was washed thoroughly w i t h c o l d water, f o l l o w e d by hot water. I t was d r i e d o at 110 to constant weight. Where platinum was present i n l a r g e amount wi t h p a l l a d i u m , a second p r e c i p i t a t i o n was c a r r i e d out to check f o r any contamination. For t h i s the p r e c i p i t a t e was decom-posed by d i g e s t i o n i n a water bath with a l i t t l e aqua r e g i a and d i l u t e d with an equal volume of water. The r e s u l t i n g s o l u t i o n was 15 d i l u t e d with water and p a l l a d i u m was r e p r e c i p i t a t e d as the dimethyl glyoxime complex i n the c o l d . Rhodium or i r i d i u m o x i d e s from the sodium carbonate f u s i o n were f i l t e r e d o f f on Whatman 41 f i l t e r paper. The p r e c i p i t a t e o was washed thoroughly with water, d r i e d i n an oven at 110 , then i n c i n e r a t e d i n a platinum c r u c i b l e . F i n a l r e d u c t i o n was with hydrogen. E s t i m a t i o n of Other Metals 49 T i n was estimated" as the oxide f o l l o w i n g p y r o h y d r o l y s i s . Germanium was weighed as magnesium ortho germanate or as german-49 ium s u l f i d e . F u r t h e r d e t a i l s i n i n d i v i d u a l o p e r a t i o n w i l l be found under each compound. 16 CHAPTER 2: General P h y s i c a l Techniques I n t r o d u c t i o n Although chemical a n a l y s i s i s a p r e l i m i n a r y to the i d e n t i -f i c a t i o n of a compound, unambiguous c h a r a c t e r i z a t i o n i s o f t e n o n l y p o s s i b l e a f t e r p h y s i c a l examination. Vapour pressure measure-ment, m e l t i n g and b o i l i n g p o i n t d e t e r m i n a t i o n , i n f r a r e d s p e c t r o -s c o p i c examination, magnetic s u s c e p t i b i l i t y measurement and X-ray powder photography are p a r t i c u l a r l y v a l u a b l e . Of these, X-ray powder photography i s of prime importance i n the study of the l e s s v o l a t i l e f l u o r i d e s . Even i f i t i s i m p o s s i b l e or u n d e s i r a b l e to proceed to a f u l l s t r u c t u r a l i n v e s t i g a t i o n , comparisons with x-ray photographs of known m a t e r i a l s may e s t a b l i s h isomorphism or i n d i -c a t e the p u r i t y of a m a t e r i a l . Magnetic measurements are of value i n e s t a b l i s h i n g v a l e n c y and o c c a s i o n a l l y s t e r e o c h e m i s t r y . I n f r a -r e d s p e c t r a , although of prime s t r u c t u r a l v alue i n the case of v o l a t i l e f l u o r i d e s i s n e v e r t h e l e s s a u s e f u l s t r u c t u r a l adjunct f o r the l e s s v o l a t i l e f l u o r i d e s a l s o . X-ray powder photographs X-ray powder samples of the i n v o l a t i l e f l u o r i d e s were pre-pared i n quartz c a p i l l a r i e s (0.3 or 0.5 mm d i a ) . For r e a c t i v e compounds, the c a p i l l a r i e s were s e a l e d under vacuum. N i c k e l shot was used to powder the m a t e r i a l from which samples were taken. To ensure a p e r f e c t s e a l i n the c a p i l l a r y samples, the drawn end of the x-ray c a p i l l a r y was dipped momentarily i n t o molten wax. 17 X-ray powder photographs were taken u s i n g a 14.32 cm. diameter, General E l e c t r i c Camera. T h i s camera employs Straumanis l o a d i n g . N i c k e l - f i l t e r e d ( u s i n g a 0.089 cm. t h i c k Ni f o i l ) Cu-Koc r a d i a t i o n ( X = 1.5418 ft) was the source. The x-ray tube was operated at 35 k i l o v o l t s and 15 m i l l i a m p s . The exposure time f o r a measureable f i l m was about 15 hours. Where i n t e n s i t y measurements were r e q u i r e d the f i l m s were developed f o r a constant i n t e r v a l of time. The f i l m s were measured with an a c c u r a t e r u l e p r ovided with a v e r n i e r ( P h i l i p s E l e c t r o n i c s , Inc.) and the c e l l parameters were determined from these measurements u s i n g a computer program IBFTC INDEXX (APPENDIX I) with an IBM 7040 computer. The program provided f o r c a l c u l a t i o n of the Bragg angles, the i n t e r p l a n a r spacings 2 56 d, 1/d v a l u e s and the Nelson R i l e y E x t r a p o l a t i o n F u n c t i o n . I n t e n s i t i e s were estimated v i s u a l l y except f o r q u a n t i t a t i v e work, when a H i l g e r and Watts microphotometer was used. Magnetic measurements Magnetic s u s c e p t i b i l i t y measurements were made by the Gouy method. The apparatus was s i m i l a r to t h a t d e s c r i b e d by F i g g i s 57 'SR and Nyholm. The d e t a i l e d arrangement has been d e s c r i b e d . A thermostat c o n t r o l l e d compartment allowed the s u s c e p t i b i l i t y to be measured at any d e s i r e d temperature. With our equipment, the mean temperature of the specimen was c o n t r o l l a b l e to 0.1°. I n i t i a l l y a f i n e l y powdered sample was packed i n t o a 11.4 cm x 3 mm (dia) sample tube (quartz or Pyrex) i n s i d e a drybox and s e a l e d under vacuum. The specimen was then suspended 18 from the bottom of the balance pan, by means of a l i g h t brass c h a i n . Under i d e a l c o n d i t i o n s , the bottom of the tube was at the c e n t r e of the pole f a c e s with the top i n the r e g i o n of n e g l i g i b l e f i e l d . With our arrangement the f i e l d was v a n i s h i n g l y s m a l l at 8.7 cm from the c e n t r e of the pole f a c e s . Mercury c o b a l t t e t r a t h i o c y a n a t e , HgCoCCNS)^, recommended 59 by F i g g i s and Nyholm, was used as the standard f o r paramag-n e t i c measurements. The molar s u s c e p t i b i l i t i e s were c o r r e c t e d 60 f o r the diamagnetic c o n t r i b u t i o n s of the c o n s t i t u e n t i o n s . Wherever the Curie-Weiss law was obeyed, the molecular f i e l d c onstant was determined by a p p l y i n g the l e a s t squares a p p r o x i -mation f o r a set of at l e a s t f o u r t e e n independent measurements. A program "IBFTC APPROX" was run i n the IBM 7040 computer f o r t h i s purpose (See APPENDIX I I ) . For diamagnetic s u s c e p t i b i l i t y measurements s p e c t r o s c o p i c a l l y pure benzene was used: as the standard (*Xg = -0.706 x 10~ c.g.s. u n i t s at 2 0 ° ) . I n f r a r e d a b s o r p t i o n s p e c t r a S o l i d phase i n f r a r e d a b s o r p t i o n s p e c t r a were recorded from 2000 - 400 c m - 1 with a Perkin-Elmer model 421, and from 800 -400 c m - 1 with a P.E. model 21 spectrophotometer. Powdered samples were pressed between two s i l v e r c h l o r i d e windows. I t was very d i f f i c u l t to reduce the p a r t i c l e s i z e except by pro-longed g r i n d i n g i n an agate mortar and p e s t l e . A f t e r s p r e a d i n g the substance i n a t h i n l a y e r between the s i l v e r c h l o r i d e windows, i t was s e a l e d at the edges with c e l l o p h a n e tape. A l l manipulations were c a r r i e d out i n a dry box. 19 M e l t i n g p o i n t M e l t i n g p o i n t s were determined u s i n g a microscope with a hot stage ERNST LEITZ Model 350 (GMBH WETZLAR-Germany) with temperature r e a d i n g through the eye-piece. T h i s instrument has o o a temperature range of -20 to +350 . The speed with which the temperature was r a i s e d i n the neighbourhood of m e l t i n g p o i n t was approximately 3° per minute. 20 CHAPTER 3: General P r e p a r a t i v e Techniques  F l u o r i n e Handling A l l apparatus f o r h a n d l i n g f l u o r i n e was enclosed i n a w e l l -v e n t i l a t e d hood. A g e n e r a l purpose assembly i s re p r e s e n t e d i n F i g . 1. High pressure f l u o r i n e supply tanks were p l a c e d i n pro-t e c t i v e metal e n c l o s u r e s . The i n s t a l l a t i o n of double v a l v e s (and a b a l l a s t tank where necessary) between the hig h pressure source and the m a n i f o l d f a c i l i t a t e d the smooth r e d u c t i o n of f l u o r i n e p r e s s u r e . The m a n i f o l d was c o n s t r u c t e d mainly from Teflon-packed s t a i n l e s s s t e e l v a l v e s (Autoclave Engineers S e r i e s 30 VM) and the compression f i t t i n g s s u p p l i e d f o r use with these v a l v e s . Monel metal Swagelok compression f i t t i n g s were used f o r f r e q u e n t l y d i s c o n n e c t e d j o i n t s . S i l v e r s o l d e r (American Platinum Works No. 355) was used o n l y f o r making s p e c i a l j o i n t s or adaptors. The h i g h pressure s i d e of the apparatus was welded to a Monel Bourden tube gauge. The low pre s s u r e s i d e was made of 1/16 i n . monel t u b i n g and A431 Hoke v a l v e s . A H e l i c o i d gauge was i n c o r p o r a t e d i n t h i s part of the system to permit pressure measurements of l e s s than 1000 mm. Solder tube f i t t i n g s were used with the A431 Hoke v a l v e s to make e x c e l l e n t vacuumtight j o i n t s . The v a l v e s were a l l Helium leak t e s t e d at the bellow s . Although the p u r i t y of the f l u o r i n e s u p p l i e d by A l l i e d Chemicals was claime d to be b e t t e r than 98%, i t was a r o u t i n e p r e c a u t i o n to pass the f l u o r i n e over a sodium f l u o r i d e bed before 21 F i g . 1 A General Purpose F l u o r i n e L i n e M.V. 30,000 p . s . i . monel v a l v e . M.X. Monel c r o s s . M.T. Monel tee. G-^ . Monel Bourden gauge, 400 l b . p . s . i . G 2. Monel Bourden gauge, 1000 mm. Hg. C. 30,000 p . s . i . seamless monel t u b i n g 3/8 i n . o.d., 1/8 i n . i . d . , s i l v e r s o l d e r e d to 3/8 i n . o.d. copper t u b i n g . F. 3/8 i n . f l a r e f i t t i n g . K. 3/8 i n . 30,000 p . s . i . t u b i n g , s i l v e r s o l d e r e d to 1/4 i n . monel t u b i n g . Hi and H 2. Hoke A431 and A432 v a l v e s r e s p e c t i v e l y . B. F l e x i b l e copper bellows. S.L. Soda lime tower. B.V. 3/8 i n . bore t e f l o n seated b a l l v a l v e . , J . Connection f o r vacuum pumps. H.P. High pressure f l u o r i n e o u t l e t . L.P. Low pressure f l u o r i n e o u t l e t v i a "Swagelok compression f i t t i n g s . S. Swagelok o u t l e t f o r apparatus r e q u i r i n g f l u o r i n e d i l u t e d with n i t r o g e n . 23 use. The presence of even t r a c e s of moisture or hydrogen f l u o r i d e would b r i n g about h y d r o l y s i s of the product as a r e s u l t of the c y c l e : MF n + H 2 0 — > MOF n_ 2 + 2HF 4HF +• S i 0 2 — * S i F 4 + 2H 20 As an added p r e c a u t i o n , wherever p o s s i b l e , the f l u o r i n e was p u r i -f i e d by p a s s i n g through t r a p s c o o l e d i n l i q u i d oxygen. The e x i t end of the m a n i f o l d l e d to a s o d a l i n e scrubber, c o l d t r a p , and f i n a l l y to the vacuum pump. The r e s i s t e n c e of n i c k e l to a t t a c k by f l u o r i n e depends on the forma t i o n of a p r o t e c t i v e f i l m . Before being put i n t o s e r v i c e , a l l equipment was thoroughly c l e a n s e d of o r g a n i c matter and pre-f l u o r i n a t e d by c a u t i o u s , stepwise a d d i t i o n of f l u o r i n e u n t i l the c o n d i t i o n s of pressure and temperature were s i m i l a r to those subsequently encountered i n the experimental work. In r e a c t i o n s i n v o l v i n g f l u o r i n e and other f l u o r i n a t i n g agents i t was necessary to a v o i d rubber, tapgrease, and other o r g a n i c matter. Reactions i n v o l v i n g elemental f l u o r i n e P r e p a r a t i o n s i n v o l v i n g the use of elemental f l u o r i n e e i t h e r employed a flow method with p a r t i a l p r e s s u r e s of f l u o r i n e up to one atmosphere or e l s e a c l o s e d system c o n t a i n i n g f l u o r i n e g e n e r a l l y much i n excess of one atmosphere p r e s s u r e . Flow system p r e p a r a t i o n s employed the low pressure f l u o r i n e s i d e of the f l u o r i n e assembly d e s c r i b e d above e a r l i e r . Copper t u b i n g , 1/4 i n . diam. was used f o r the d e l i v e r y and e x i t t u b i n g f o r the r e a c t o r . In the low pressure l i n e , d i r e c t l y a f t e r the pressure 24 r e d u c i n g needle v a l v e s , was a blow-off c o n s i s t i n g of a s i l v e r -s o l d e r e d T - j o i n t of 1/4 i n . diam. copper t u b i n g with i t s o u t l e t d i p p i n g i n t o a K e l - F tube c o n t a i n i n g " F l u o r o l u b e o i l " (Hooker Chemical Co., FS.5). The blow-off served the dual purpose of a s a f e t y d e v i c e and a crude flow meter. The flow r a t e was measured by c o u n t i n g bubbles emerging at the blow-off when the needle v a l v e (Hoke A431) at the e x i t of the low pressure l i n e was c l o s e d . G e n e r a l l y i n a flow r e a c t i o n , the f l u o r i n e was ( c a r r i e d i n a stream of dry n i t r o g e n which was i n t r o d u c e d by way of a copper T - j o i n t . A Hoke A431 v a l v e c o n t r o l l e d the n i t r o g e n flow. The r e a c t o r was p r o v i d e d with a g l a s s f o r e - t r a p . The r e a c t o r i t s e l f was u s u a l l y a quartz tube of 25 mm. diam. 30 cm. i n l e n g t h , and tapered at one end to a 10 mm. diam. graded j o i n t , succeeded by s e r i e s of g l a s s t r a p s provided to c o l l e c t v o l a t i l e products, the l a s t being connected to the vacuum l i n e . Those t r a p s intended f o r the condensation of the r e q u i r e d v o l a t i l e products were provided with b r e a k s e a l s . In a t y p i c a l f l u o r i n a t i o n the metal to be f l u o r i n a t e d was h e l d i n a n i c k e l boat c o n t a i n e d i n the quartz tube. D i l u t e d f l u o r i n e was passed i n t o the r e a c t i o n system with a l l the t r a p s c o o l e d i n l i q u i d oxygen. The metal was heated, i f necessary, to i n i t i a t e r e a c t i o n . S i l i c o n t e t r a f l u o r i d e c o l l e c t e d i n the t r a p s along w i t h the v o l a t i l e products. The f l u o r i n e supply was shut o f f when the r e a c t i o n was complete and the system was purged with n i t r o g e n . The e n t i r e system was then evacuated and any s i l i c o n o t e t r a f l u o r i d e was removed by warming the t r a p s to -78 . The t r a p s c o n t a i n i n g the products were drawn o f f under vacuum. 25 High Pressure Reactions Argon arc-welded monel-metal c y l i n d r i c a l cans of 2 i n . outer diam. and 3 i n . ; long and of 1/8 i n . w a l l t h i c k n e s s provided with bras s Hoke A431 v a l v e s were used as r e a c t i o n v e s s e l s . R eactions i n which the products were expected to be i n v o l a t i l e r e q u i r e d the use of cans provided with a l i d h e l d by s t r o n g b o l t s . Such v e s s e l s were used with t e f l o n or aluminium gaskets, the l a t t e r being p r e f e r r e d f o r high temperature work although i t was more d i f f i -c u l t to o b t a i n leak t i g h t v e s s e l s with these gaskets.. The r e a c t o r s were t e s t e d f o r p r e s s u r e s up to 300 p . s . i . R e a c t i o n s I n v o l v i n g Halogen F l u o r i d e s and Selenium T e t r a f l u o r i d e . I n t r o d u c t i o n . As i o n i z i n g s o l v e n t s with convenient l i q u i d ranges, bromine t r i f l u o r i d e (m.p. 9°, b.p. 127°), i o d i n e p e n t a f l u o r i d e (m.p. 10°, b.p. 9 8 ° ) , and selenium t e t r a f l u o r i d e (m.p. -10°, b.p. 100°) have been of value i n the p r e p a r a t i o n of b i n a r y and t e r n a r y f l u o r i d e s . Bromine t r i f l u o r i d e which i s a powerful f l u o r i n a t i n g agent i s a l s o an e x c e l l e n t s o l v e n t . Iodine p e n t a f l u o r i d e i s an i n f e r i o r s o l v e n t to bromine t r i f l u o r i d e but i s more d i f f i c u l t to o x i d i s e and reduce than the l a t t e r . Selenium t e t r a f l u o r i d e i s a good i o n i z i n g s o l v e n t and i s a b e t t e r r e d u c i n g agent than e i t h e r BrF3 or I F 5 . Experiments i n v o l v i n g these s o l v e n t s were g e n e r a l l y conducted i n apparatus a k i n to t h a t r e p r e s e n t e d i n F i g . 2. The system con-s i s t e d of Pyrex and metal s e c t i o n s , the s e c t i o n s being j o i n e d by swagelok compression f i t t i n g s with t e f l o n f e r r u l e s . The metal p o r t i o n of the system was c o n s t r u c t e d of 1/4 i n . o.d. monel t u b i n g , Hoke A431 needle v a l v e s and K e l - F t r a p s . The g l a s s p o r t i o n 26 of the apparatus was l i n k e d to the metal s e c t i o n by way of a three way stopcock which permitted e i t h e r e v a c u a t i o n of the g l a s s system or i n t r o d u c t i o n of n i t r o g e n gas to i t . U s u a l l y the r e a c -t i o n i n the f l u o r o s o l v e n t was c a r r i e d out i n a quartz bulb j o i n e d to a Pyrex m a n i f o l d v i a a graded s e a l . The ma n i f o l d was provided with g l a s s t r a p s at each end and one end of t h i s system was attached to the s o l v e n t supply c y l i n d e r and the other to the three way s t o p -cock . The e n t i r e apparatus was d r i e d by baking under^vacuum. I n i t i a l l y a plug of s o l i d s o l v e n t was formed at P ( F i g . 2) by c o o l i n g the neck of t r a p B i n l i q u i d oxygen. T h i s prevented f u r t h e r m a t e r i a l condensing i n the system beyond the po i n t P. At t h i s stage l i q u i d oxygen baths were p l a c e d around a l l the t r a p s and the s o l v e n t was allowed to d i s t i l l i n t o the t r a p A near the c y l i n d e r . When s u f f i c i e n t s o l v e n t had been t r a n s f e r r e d , the source was shut o f f and the g l a s s t u b i n g was drawn down and s e a l e d with a flame near the c y l i n d e r c o n n e c t i o n . The s o l v e n t was subsequently d i s t i l l e d i n t o the s i l i c a r e a c t i o n bulb C c o o l e d with l i q u i d oxygen. The plu g of the s o l v e n t meanwhile served as an e f f e c t i v e vacuum s e a l . I f l o s s of vacuum o c c u r r e d by v i r t u e of s o l v e n t i n t e r a c t i o n with the c o n t a i n e r , e.g. as wit h the r e a c t i o n of bromine t r i f l u o r i d e w i t h g l a s s to form oxygen and s i l i c o n t e t r a f l u o r i d e , the vacuum was r e e s t a b l i s h e d by momentarily m e l t i n g the plug with a hot a i r blower, pumping o f f the oxygen and s i l i c o n t e t r a f l u o r i d e , and f i n a l l y renewing the plu g of BrF^. When the t r a n s f e r e n c e was complete the plu g was melted and dry n i t r o g e n or dry a i r was T O P U M P I N G L I N E * | Hoke 4IIA FIGURE 2. Hoke A43I Hoke 411 A Hoke A 431 Hoke A 431 Hoke A43I Kel -F trop t TO PUMPING LINE A APPARATUS FOR REACTIONS INVOLVING FLUORO-SOLV ENTS y ** TO SOLVE NT SUPPLY CYLINDER 28 slo w l y admitted through the t r a p s c o o l e d i n l i q u i d oxygen and the system was brought to atmospheric p r e s s u r e . The r e a c t i o n bulb was brought c a u t i o u s l y to room temperature. Reactions i n v o l v i n g bromine t r i f l u o r i d e were c a r r i e d out with c a r e . S e v e r a l metals, metal o x i d e s and i o d i d e s r e a c t v i g o r o u s l y with bromine t r i f l u o r i d e with the e v o l u t i o n of s u f f i c i e n t heat to r a i s e the r e a c t a n t s to incandescence. Such r e a c t i o n s were c o n t r o l l e d by j u d i c i o u s c o o l -i n g with l i q u i d oxygen. When the r e a c t i o n was complete, the excess r e a c t a n t and any v o l a t i l e products were d i s t i l l e d under vacuum i n t o the c o l d t r a p s . In some i n s t a n c e s i t was necessary to heat the i n i t i a l l y formed product (e.g. a BrFg adduct) to o b t a i n the d e s i r e d m a t e r i a l . In such cases, the product i n the bulb was heated under vacuum to the r e q u i r e d temperature f o r s e v e r a l hours before being drawn o f f . The excess of bromine t r i f l u o r i d e from the r e a c t i o n was des t r o y e d by pouring i t i n t o an excess of carbon t e t r a c h l o r i d e . Excess of selenium t e t r a f l u o r i d e or i o d i n e p e n t a f l u o r i d e was destroyed by pouring i t i n t o an excess of c o n c e n t r a t e d s u l f u r i c a c i d . The s o l u t i o n was then poured s l o w l y on to a l a r g e excess of running water. CHAPTER 4: DETAILED EXPERIMENTAL WORK 29 A. MISCELLANEOUS REAGENTS Noble metals of s p e c t r o s c o p i c grade, and germanium d i o x i d e , caesium f l u o r i d e , potassium f l u o r i d e of AnalaR grade, were obtained from Johnson, Mathey and Company, London. T i n t e t r a i o d i d e was s u p p l i e d by A l f a I n o r g a n i c s Inc., Montreal. F l u o r i n e i n c y l i n d e r s of 5 l b s . c a p a c i t y , at 400 p . s . i . p r e s s u r e , was from the General Chemical D i v i s i o n , A l l i e d Chemical C o r p o r a t i o n , New York. I t was d i s t r i b u t e d by The Matheson Co., East R u t h e r f o r d , New J e r s e y . Oxygen d i f l u o r i d e p r ovided i n a c y l i n d e r under 100 p . s . i . pressure was a g i f t from the General Chemical Research Lab., A l l i e d Chemical C o r p o r a t i o n , Morristown, New J e r s e y . Bromine t r i f l u o r i d e , bromine p e n t a f l u o r i d e and i o d i n e penta-f l u o r i d e were o b t a i n e d i n c y l i n d e r s from The Matheson Co., New J e r s e y . They were p u r i f i e d by t r a p to t r a p d i s t i l l a t i o n before use. Selenium t e t r a f l u o r i d e was produced by d i r e c t f l u o r i n a t i p n of selenium metal a f t e r the method d e s c r i b e d by Aynsley, Peacock and Robinson. P a l l a d i u m dibromide was prepared by d i s s o l v i n g s p e c t r o -s c o p i c a l l y pure p a l l a d i u m sponge i n aqua r e g i a , t h i s s o l u t i o n being evaporated s e v e r a l times to dryness with 48% hydrobromic a c i d c o n t a i n i n g bromine. The brown r e s i d u e was f i n a l l y d r i e d at 70° in_ vacuo. A sample was analysed f o r p a l l a d i u m f^Found: Pd, 39.5. C a l c . f o r Pdfir2: Pd, 39.9%.] 30 Platinum tetrabromide was prepared by H a l b e r s t a d t ' s 62.63 m o d i f i c a t i o n of the method of Meyer and Z u b l i n . Platinum sponge was heated to 1 8 0 ° i n a s e a l e d tube with excess of 2 :1 hydrobromic a c i d (48%)/bromine f o r 24 h r s . The s o l u t i o n was f i l t e r e d to remove any platinum dibromide, evaporated to dr y -ness, then heated to 1 8 0 ° . The r e s i d u e was r e d i s s o l v e d i n water, and the ev a p o r a t i o n and d r y i n g repeated. Platinum t e t r a -bromide was ob t a i n e d as d e e p - v i o l e t c r y s t a l s . QFouhd: Pt, 3 8 . 3 : C a l c . f o r P t B r 4 : Pt, 37.9% J . Rhodium t r i c h l o r i d e - Rhodium metal was heated with a s l i g h t excess of c h l o r i n e at 4 5 0 ° , f o r 24 h r s . , i n a monel r e a c t o r . Excess c h l o r i n e was removed under vacuum. Rhodium t r i c h l o r i d e prepared i n t h i s way was a r e d brown c r y s t a l l i n e s o l i d . f^Found: Rh, 4 9 . 3 . C a l c . f o r R h C l 3 : Rh, 49.2%J. Rhodium t r i b r o m i d e - Rhodium metal was r e f l u x e d with an excess of bromine/hydrobromic a c i d mixture f o r 48 h r s . The excess bromine/hydrobromic a c i d was d i s t i l l e d o f f at low pr e s -sure and the s o l u t i o n was evaporated and d r i e d i n vacuo at 1 0 0 ° . [Found: Rh, 2 9 . 8 . C a l c . f o r RhBr 3: Rh, 30. 03%^). 31 B. PALLADIUM FLUORIDES (1) THE PALLADIUM TRIFLUORIDE, BROMINE TRIFLUORIDE ADDUCT, B r F 3 . P d F 3 . (a) P r e p a r a t i o n . The adduct was prepared e s s e n t i a l l y by the method gi v e n by Sharpe. x Bromine t r i f l u o r i d e was d i s t i l l e d i n t o a r e a c t i o n bulb c o n t a i n i n g p a l l a d i u m dibromide. Reaction was i n i t i a t e d by g e n t l e warming of the bulb to 40°. Vigorous r e a c t i o n between the bromine t r i f l u o r i d e and p a l l a d i u m dibromide was c o n t r o l l e d by o c c a s i o n a l l y c o o l i n g the bulb with l i q u i d oxygen. A f t e r the pa l l a d i u m bromide had d i s s o l v e d completely, the bromine and excess bromine t r i f l u o r i d e were pumped i n t o two c o l d t r a p s . When a l l of the v o l a t i l e substance had been removed, a dark brown s o l i d remained. The r e a c t i o n bulb was then drawn o f f under vacuum. QFound: F, 34.2; Pd, 36.7. C a l c . f o r P d F 3 . B r F 3 : F, 38.0; Pd, 3 5 . 5 % ] . X-ray powder photographs showed o n l y f a i n t broad l i n e s c h a r a c t e r i s t i c of PdF 3 a g a i n s t a heavy background. (b) Magnetic S u s c e p t i b i l i t y Data f o r P d F 3 . B r F 3 . Magnetic measurements were made on the B r F 3 . P d F 3 adduct i n the tempera-t u r e range 77-293°K. As may be seen from the r e s u l t s shown i n Table I the s u s c e p t i b i l i t y obeys the Curie-Weiss law, l / j t M 0 C ( T +6 ), with Q = 5.3°. The d e v i a t i o n of each observed value from the i d e a l C u r i e Weiss value (obtained by l e a s t squares refinement) i s i n d i c a t e d . The d e v i a t i o n s are w i t h i n the probable experimental c e r t a i n t y . The magnetic moment at 293°K i s ^ U e f f = 1.81 B.M. 32 TABLE I. Molar S u s c e p t i b i l i t y Data f o r P d F 3 . B r F 3 . Temp l o ! l M ( o b s ) l O ^ j C l d e a l ) - Temp 10*k M(obs) 10 6j£ M(ideal)-(°K) ( i n c . g. s . u n i t s ) ( i n c.g.s. u n i t s ) (°K) ( i n c.g.s. u n i t s ) ^ M ( o b s ) ( i n c.g.s. u n i t s ) 77 5229 345.6 213.5 1845.0 8.5 87 4279 -75.1 231 1651 -49.4 107 3574 -4.5 248.5 1534 -49.2 127. 5 3034 8.0 264.5 1474 -15.3 146 2649 -6.9 283.0 1422 28.3 171. 5 2273 0.2 289.6 1383 20.5 195. 5 1992 -9.1 293.0 1366 19.0 (2) PALLADIUM(II) HEXAFLUOROPALLADATE (IV) , P d 2 + C P d F g l 2-(a) P r e p a r a t i o n . x The bromine t r i f l u o r i d e adduct P d F 3 . B r F 3 prepared as d e s c r i b e d above was decomposed at 220° under vacuum. The r e s i d u e was black p a l l a d i u m ( I I ) h e x a f l u o r o p a l l a d a t e ( I V ) . X-ray powder photographs showed o n l y l i n e s c h a r a c t e r i s t i c of "PdF 3". A n a l y s i s was by p y r o h y d r o l y s i s . [Found: F, 34.2; Pd, 65.1. C a l c . f o r P d 2 + [ P d F 6 l 2 ~ : F, 34.8; Pd, 65.2%H. (b) Magnetic S u s c e p t i b i l i t y Data f o r Pd 2 +[PdFg] 2 ~ . Magnetic s u s c e p t i b i l i t y data f o r P d 2 + C P d F g l 2 ~ f o r the temperature range 80-293°K are reco r d e d i n Table I I . The s u s c e p t i b i l i t y obeys the Curie-Weiss law with 6 = 28°, and at 293°K the e f f e c t i v e magnetic moment / ^ e ± ± = 2.88 B.M. Observed d e v i a t i o n s from i d e a l behaviour are w i t h i n the experimental u n c e r t a i n t y . 33 TABLE I I . Molar S u s c e p t i b i l i t y Data f o r Pd 2 +CPdFg] 2-Temp o ( K) 10V (obs) M ( i n c.g.s. u n i t s ) 1 0 S C M ( i d e a l ) -DC M ( o b s ) ( i n c.g.s. u n i t s ) Temp 10 6 D^ M(obs) (°K) ( i n c.g.s. u n i t s ) 1 0 ^ M ( i d e a l ) X M ( o b s ) ( i n c.g.s. u n i t s ) 80 10173 -150.7 203 4596 -48.55 107 7964 -27.75 223 4317 45.20 122 7352 169.08 240 4001 1.99 135 6607 3.32 263 3689 8.03 149 6087 10.99 276 3497 -25.63 166 5533 -5.62 286 3385 -24.80 183 5071 -17.56 298 3314 30.41 (c) I n f r a r e d Spectrum. An : i n f r a r e d spectrum of s o l i d p a l l a d i u m ( I I ) h e x a f l u o r o p a l l a d a t e ( I V ) was recorded from 2000-450 c m - 1 u s i n g a Perkin-Elmer model 421 spectrophotometer. The spectrum was c h a r a c t e r i s e d by a s t r o n g a b s o r p t i o n at 610-575 and a weak shoulder at 660 cm-''". (d) D i f f u s e R e f l e c t e n c e Spectrum. Powdered p a l l a d i u m ( I I ) h e x a f l u o r o p a l l a d a t e ( I V ) gave a broad a b s o r p t i o n band i n the r e g i o n 3800-7200 ft. No f i n e s t r u c t u r e was observed. (3) PALLADIUM(II) HEXAFLUOROPLATINATE(IV), Pd 2 + C P t F g ] 2 " . (a) P r e p a r a t i o n . P a l l a d i u m ( I I ) h e x a f l u o r o p l a t i n a t e ( I V ) was prepared from a mixture of p a l l a d i u m dibromide and platinum tetrabromide i n 1:1 molar r a t i o , by d i s s o l v i n g the mixture i n bromine t r i f l u o r i d e at 30-50 to give a red-brown s o l u t i o n , 34 Removal of the v o l a t i l e s under vacuum l e f t a brown s o l i d . T h i s on h e a t i n g to 180° i n vacuo gave a l i g h t brown powder. 2+ 2 — Samples of Pd CPtFgl ~ prepared i n t h i s way were p o o r l y c r y s t a l l i n e . However the c r y s t a l l i n i t y was improved by h e a t i n g the product to 200° i n a monel r e a c t o r i n one atmosphere of f l u o r i n e f o r 24 h r s . Q i 2 — A n a l y s i s of Pd CPtFgH ~ was by p y r o h y d r o l y s i s . The t o t a l p a l l a d i u m and platinum content was determined by r e d u c t i o n i n o f'-hydrogen at 400 with a p p r o p r i a t e c o r r e c t i o n s a p p l i e d f o r the p a l l a d i u m content. P a l l a d i u m was s e p a r a t e l y estimated as the dimethyl glyoxime complex. [.Found: F, 27.0; Pd, 25.1; Pd + Pt, 72.9. Required f o r P d + 2 [ P t F g " ] 2 _ : F, 27.4; Pd, 25.6; Pd + Pt, 7 2 . 6 % J . (b) General P r o p e r t i e s . P a l l a d i u m ( I I ) h e x a f l u o r o p l a t i n a t e ( I V ) i s s i m i l a r to a l k a l i n e e a r t h h e x a f l u o r o p l a t i n a t e s i n i t s p h y s i -c a l p r o p e r t i e s . I t i s not very r e a c t i v e with water, but i s s l o w l y h y d r o l y s e d , even in, moist a i r . 2 + 2 — (c) X-ray Powder Data f o r Pd [PtFg~3 . The s a l t i s isomorphous with Pd z +[j?dF63) • The observed x-ray r e f l e c t i o n s have been indexed on the b a s i s of a rhombohedral u n i t c e l l , as i n d i c a t e d i n Table I I I , with a = 5.55 + 0.01 ft, oC = 54.0 + 0.02°, V * o 3 103.8 A , Z = 1, D c a i c = 6.64 g/c.c. 35 TABLE I I I . C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data f o r P d 2 + [ P t F 6 " j 2 ~ h k l c a l c . obs. Jobs. I l l 0.045 0.045 2 100 0.058 0.058 4 110 0.073 0.074 10 211 0.132 0.133 9 T01 0.158 0.159 5 222 0.180 0.179 2 120 0.203 0.204 5 111 0.216 0.215 2 200 0.232 0.232 6 220 0.290 0.291 6 322 0.297 0.298 2 321 0.338 0.337 10 332 0.372 0.371 5 121 0.389 0.390 9 310 0.448 0.449 7 211 0.474 0.475 6 320 0.493 0.492 2 422 0.530 0.528 4 433 0.552 0.549 4 432 0.562 0.559 3 421 0.613 0.614 2 202 0.632 0.634 3 36 1/d 2 h k l c a l c . obs. 141 0.653 0.653 431 0.688 0.686 301 0.705 0.705 132 0.764 0.763 410 0.809 0.809 222 0.863 0.861 352 0.867 0.864 400 0.922 0.922 521 1.002 1.000 231 1.020 1.020 T41 1.080 1.078 321 1.106 1.104 232 1.151 1.154 541 1.183 1.179 654 1.280 1.280 530 1.314 1.311 411 1.337 1.336 233 1.396 1.391 303 1.422 1.419 241 1.467 1.467 204 1.494 1.490 242 1.554 1.549 151 1.599 1.596 611 1.636 1.636 754 1.646 1.646 37 2+ 2 -(d) Magnetic S u s c e p t i b i l i t y Data f o r Pd [PtF g l . The magnetic s u s c e p t i b i l i t y data f o r Pd 2 +[ptFg3 i n the temperature range 80-293°K are given i n Table IV. The s u s c e p t i b i l i t y obeys the C u r i e -Weiss law, with 0= 1.0° and the magnetic moment at 293°K A e f f = 2.72 B.M. D e v i a t i o n s are w i t h i n the experimental u n c e r t a i n t y . TABLE IV. Molar S u s c e p t i b i l i t y Data f o r P d 2 + [ P t F < D Temp l O ^ o b s ) l o 6X M( i d eaD- Temp 10 * t M ( o b s ) 1 0 6 X M ( i d e a l ) (°K) ( i n c.g.s. u n i t s ) X M ( o b s ) v ( i n c.g.s. u n i t s ) (°K) ( i n c.g.s. u n i t s ) X M ( o b s ) ( i n c.g.s. u n i t s ) 80 11246 -30.0 211 4246 -31 102 9069 254.7 241 3701 -45.2 120 7671 176.7 258 3514 13.92 137 6662 -87.3 262 3469 22.2 149 5966 -81.8 279 3244 6.7 171 5226 -47.1 287 3169 21.7 187 4680 -143.7 294 3087 14.4 .(e) I n f r a r e d Spectrum. The i n f r a r e d a b s o r p t i o n of the s o l i d was observed to be an i n t e n s e broad peak at 600-560 cm" with a weak shoulder at 660-675 cm *. 38 (4) PALLADIUM(II) HEXAFLUOROGERMANATE(IV) , Pd 2 +QGeFg"j 2~. (a) P r e p a r a t i o n . Exothermic r e a c t i o n of bromine t r i f l u o r i d e with a. 1:1 molar r a t i o mixture of p a l l a d i u m dibromide and germanium d i o x i d e began at 10-15°, with the l i b e r a t i o n of bromine and oxygen. The r e a c t i o n was r e a d i l y c o n t r o l l e d by a p p r o p r i a t e c o o l i n g with l i q u i d oxygen. Care was r e q u i r e d because of the l a r g e volume of evolved oxygen when the quan-t i t y of germanium d i o x i d e was of the order of 1 g. or more. The removal of excess of BrFg under vacuum at room temperature l e f t a dark brown s o l i d c o n t a i n i n g bromine t r i f l u o r i d e . By r a i s i n g the temperature to 150° and m a i n t a i n i n g a vacuum, p a l l a d i u m ( I I ) hexafluorogermanate(IV) was o b t a i n e d . A n a l y s i s was by p y r o h y d r o l y s i s at 350°. F l u o r i n e and pa l l a d i u m were determined and germanium o b t a i n e d by d i f f e r e n c e . [^Found: F, 38.2; Pd, 36.4; Ge, 25.4. Required f o r P d 2 + L G e F 6 l 2 ~ : F, 38.9; Pd, 36.3; Ge, 24.8%.] (b) General P r o p e r t i e s . P a l l a d i u m ( I I ) hexafluorogermanate(IV) i s a dark brown s o l i d . I t i s r e a d i l y h y d r o l y s e d by water, hydrated p a l l a d o u s oxide being p r e c i p i t a t e d . (c) X-ray Powder Data f o r Pd C G e F 6 J • T n e s a l t i s isomorphous, 9 2 — and almost i s o d i m e n s i o n a l with Pd^ +[PdFg] . The observed x-ray r e f l e x i o n s have been indexed on the b a s i s of a rhombohedral u n i t c e l l c o n t a i n i n g one formula u n i t with a = 5.53 + 0.1 ft; od= 54.0 3 — + 0.02°; V = 102.7 ft ; Z = 1, D c a l c =4.74 g/c.c. The x-ray data i s given i n Table V. 39 TABLE V. C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data of P d 2 + t G e F g l 2 -l/d2 h k l c a l c . obs. ^obs. 111 0.045 0.045 3 ' 100 0.058 0.057 5 110 0.073 0.074 9 211 0.133 0.133 7 101 0.159 0.158 4 222 0.181 0.182 3 210 0.204 0.201 2 200 0.232 0.230 7 220 0.293 0.292 6 322 0.299 0.295 3 321 0.340 0.338 9 323 0.375 0.377 4 331 0.458 0.456 2 230 0.497 0.493 2 422 0.534 0.536 5 202 0.637 0.639 2 411 0.659 0.661 2 (d) Magnetic S u s c e p t i b i l i t y Data f o r Pd [GeF^J ~. Magnetic s u s c e p t i b i l i t y d ata were c o l l e c t e d over the temperature range 81-293°K. They are l i s t e d i n Table VI. The d e v i a t i o n from Curie-Weiss behaviour are s m a l l and are w i t h i n the experimental u n c e r t a i n t y . Least square refinement of the data f o r a C u r i e -Weiss r e l a t i o n s h i p gave a v a l u e f o r the Weiss c o n s t a n t , 6 , of 40 30°. The e f f e c t i v e magnetic moment i s almost temperature i n d e -pendent. At 293°K / ^ e f f = 2.83 B.M. TABLE VI. Molar S u s c e p t i b i l i t y Data f o r Pd2+[_GeFg~] 2 ~ . Temp (°K) l 0 6 , M ( o b s ) ( i n c.g.s. u n i t s ) 1 0 6 ^ „ ( i d e a l ) -X M(obs) ( i n c.g.s. u n i t s ) Temp (°K) 1 0 ^ M ( o b s ) ( i n c . g. s . u n i t s ) 1 0 6 V ( i d e a l ) M ^ M ( o b s ) ( i n c.g.s. u n i t s ) 81 9009 188.7 189 4480 -8.5 92 8213 182.1 206 4116 -50.4 109 6871 -184.0 233.5 3721 -12.0 121 6610 112.3 255 3440 -12.3 139 5870 60.6 267 3287 -26.3 152 5393 -3.5 283 3178 33.6 166 4888 -124.8 293 3083 35.7 (e) 2+ 2 — I n f r a r e d Spectrum of Pd QGeFgl . ~. The f o l l o w i n g a b s o r p t i o n peaks were observed. (Values i n c m - 1 ) : 745 (weak); 670 (medium s t r o n g ) , 650-560 (strong) (5) PALLADIUM(II) HEXAFLUOROSTANNATE(IV) Pd 2 +QSnFgl z ~ . (a) P r e p a r a t i o n . Pd QSnFgl was produced by the r e a c t i o n of s t o i c h i o m e t r i c mixture of p a l l a d i u m dibromide and s t a n n i c i o d i d e (or bromide) with bromine t r i f l u o r i d e . The r e a c t i o n was very v i g o r o u s when t i n t e t r a i o d i d e was used, with the e v o l u t i o n of bromine and f l u o r i d e s of i o d i n e . Excess bromine t r i f l u o r i d e and the v o l a t i l e s were removed under vacuum. The product was then o 2-heated f o r s i x hours at 180 vacuum. The c o n t a i n e r was drawn o f f under 41 A n a l y s i s was by p y r o h y d r o l y s i s at 300°. T i n was d e t e r -mined as the oxide, and f l u o r i n e and pa l l a d i u m were obtained i n the u s u a l way. QFound: F, 32.6; Sn, 35.5; Pd, 31.9. Required f o r PdSnF6: F, 33.6; Sn, 35.0; Pd, 3 1 . 4 % ] . (b) General P r o p e r t i e s . The s a l t i s s i m i l a r i n appearance and i n i t s p h y s i c a l p r o p e r t i e s to i t s germanium analogue. I t i s e a s i l y h y d r o l y s e d by water. 2+ i 2 — (c) X-ray Powder Data f o r Pd CSnFg] . The s a l t i s isomor-phous with the other Pd^LMFgl s a l t s , but i t has the l a r g e s t u n i t c e l l of the s e r i e s . The observed r e f l e x i o n s have been indexed on the b a s i s of a rhombohedral u n i t c e l l with a.= 5.70 + 0.02ft; oC= 53.13 + 0.05°; V = 110.0 ft , Z = 1; D c a l c = 5.12 g/c.c. The data i s given i n Table V I I . TABLE V I I . C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data f o r P d 2 + Q S n F 6 l 2 ~ l/d2 h k l c a l c . obs. I o b s 110 0.070 0.070 10 211 0.126 0.126 5 T o i 0.154 0.151 4 200 0.223 0.219 4 220 0.279 0.277 4 321 0.321 0.322 3 201 0.363 0.365 3 310 0.433 0.427 2 433 0.516 0.517 3 42 1/d' h k l 412 431 301 c a l c . 0.586 0.656 0.684 obs. 0.583 0.653 0.692 2+f obs, 2 2 2 2-(d) Magnetic S u s c e p t i b i l i t y Data f o r Pd z +LSnFg3 ~. The s a l t i s s i m i l a r to the other P d 2 + Q M F g j 2 - s a l t s . The observed sus-c e p t i b i l i t y again obeys the Curie-Weiss law w i t h i n the e x p e r i -mental u n c e r t a i n t y ; with Q = 30° and the magnetic moment at 293 K ef f 2.98 B.M. The data i s l i s t e d i n Table V I I I TABLE V I I I . Molar S u s c e p t i b i l i t y Data f o r Pd 2 +[SnF&] 2-Temp l o V (obs) M 1 0 6 X M ( i d e a l ) - Temp 1 0 6 X „ ( i d e a l ) M (°K) ( i n c.g.s. u n i t s ) X M ( o b s ) ( i n c.g.s. u n i t s ) (°K) ( i n c.g.s. u n i t s ) X M ( o b s ) ( i n c.g.s. u n i t s ) 86 9944 199.4 217 4512 -27.7 100 8852 171.07 233 4272 10.3 119 7585 24.1 248 4013 -17.3 141 6536 -42.1 260 3876 13.5 158 5928 -49 .7 267.5 3790 25.5 181 5228 -92.7 285 3560 5.8 193 4987 -45.1 293 3484 18.3 (6) PALLADIUM DIFLUORIDE (a) P r e p a r a t i o n Employing Selenium T e t r a f l u o r i d e . T h i s method i s an i a daption of th a t p r e v i o u s l y given by B a r t l e t t and Q u a i l . 2 2 P a l l a d i u m dibromide c o n t a i n e d i n a quartz r e a c t i o n bulb was 43 converted to the bromine t r i f l u o r i d e - p a l l a d i u m t r i f l u o r i d e adduct as d e s c r i b e d above. Selenium t e t r a f l u o r i d e was d i s -t i l l e d onto t h i s adduct and the mixture was r e f l u x e d at atmospheric pressure f o r one hour. Removal of the v o l a t i l e substances at 40° under vacuum l e f t a yellow product, f luoroselenonium hexaf l u o r o p a l l a d a t e ( I V ) , (SeF4) 2PdF4. T h i s was heated to 155° f o r an hour at atmospheric p r e s s u r e , a f t e r which the quartz c o n t a i n e r was drawn o f f under vacuum. A n a l y s i s was by p y r o h y d r o l y s i s . [Found: F, 26.0; Pd, 73.6. C a l c . f o r PdF 2: F, 26.3; Pd, 73.7%^ . X-ray powder photograph showed o n l y l i n e s c h a r a c t e r i s t i c of p a l l a d i u m d i f l u o r i d e . (b) P r e p a r a t i o n by P y r o l y s i s of P a l l a d j u m ( I I ) H e x a f l u o r o -germanate(IV) . The s a l t Pd^+LGeFgl 2 ~ was heated under vacuum to 350°, when decomposition o c c u r r e d a c c o r d i n g to the 350O equation: PdGeFg > PdF 2 + GeF4. The product was a pale l i l a c powder. X-ray powder photographs showed l i n e s a t t r i b u t a b l e to PdF 2 alone. (c) General P r o p e r t i e s . P a l l a d i u m d i f l u o r i d e v a r i e s i n c o l o u r from l i l a c to l i g h t brown depending upon i t s mode of p r e p a r a -t i o n . However a l l forms give the same x-ray photographs and g i v e s a t i s f a c t o r y a n a l y s i s . The f l u o r i d e i s h y d r o l y s e d i n moist a i r and i s decomposed by water to the hydrated o x i d e . (d) Magnetic S u s c e p t i b i l i t y Data f o r PdF 2. The magnetic s u s c e p t i b i l i t y of p a l l a d i u m d i f l u o r i d e was measured over the temperature range 77-298°K. The molar s u s c e p t i b i l i t y data i s 44 g i v e n i n Table IX. A p l o t of magnetic s u s c e p t i b i l i t y versus temperature i n d i c a t e s the compound i s a n t i f e r r o m a g n e t i c with a Neel temperature at 180°K. The s u s c e p t i b i l i t y i s f i e l d independent at 293°K. The e f f e c t i v e magnetic moment at t h i s temperature i s 1.74 B.M. TABLE IX. Molar S u s c e p t i b i l i t y Data f o r PdF2 Temp i o 6 3 C M Temp 1 0 6 X M (°K) ( i n c.g.s. u n i t s ) (°K) ( i n c.g.s. u n i t s ) 77 2100 190 3915 89 2119 201.5 3701 95 2197 217 1355 118.5 2389 237 1312 139 2662 257 1300 156.5 3056 281 1296 173 3689 292 1284 185 4005 293 1284 The data has been c o r r e c t e d f o r the diamagnetic e f f e c t of the c o n s t i t u e n t i o n s (C.M.G. C o r r . = 0.47 x 10 c.g.s./ mole) (7) PALLADIUM TETRAFLUORIDE, PdF 4 (a) P r e p a r a t i o n from Pd 2 +QPdFgJ 2 ~ . P o o r l y c r y s t a l l i n e p a l l a d i u m ( I I ) h e x a f l u o r o p a l l a d a t e ( I V ) was heated i n a monel r e a c t o r with f l u o r i n e at 200 p . s . i . to 400°. A f t e r 24 h r s . the r e a c t o r was c o o l e d to room.temperature and excess f l u o r i n e was pumped o f f . The product was b r i c k r e d . 45 A n a l y s i s was by p y r o h y d r o l y s i s at 400°. jJTound: F, 40.7; Pd, 58.5. Required f o r PdF 4: F, 41.7; Pd, 58.3%] . (b) P r e p a r a t i o n from PdF 2. P a l l a d i u m t e t r a f l u o r i d e was a l s o c o n v e n i e n t l y prepared by h e a t i n g the d i f l u o r i d e with f l u o r i n e of 100 p . s . i . at 400°. (c) P r e p a r a t i o n employing 0F 2» Oxygen d i f l u o r i d e may be used 2 — to f l u o r i n a t e e i t h e r Pd 2 +[j?dFg] or P d F 2 to the t e t r a f l u o r i d e , the gas pressure being 100 p . s . i . and the temperature 350 to 380°. (d) P r e p a r a t i o n from Pd 2 +[MFg"] 2"' s a l t s . Both f l u o r i n e and oxygen d i f l u o r i d e at 350° and at p r e s s u r e s i n excess of 100 p . s . i . o x i d i s e Pd [PtFg"] ~ to an equimolar mixture of the t e t r a f l u o r i d e s , PdF 4; P t F 4 . The deep red mixture gave a 2+ 2 — platinum t e t r a f l u o r i d e powder p a t t e r n . Pd QSnFgl i s e a s i l y o x i d i s e d by f l u o r i n e or oxygen d i f l u o r i d e at 150° to the mixed t e t r a f l u o r i d e s . The b r i c k r e d diamagnetic mixture gave a t i n t e t r a f l u o r i d e x-ray powder p a t t e r n , the p a l l a d i u m t e t r a f l u o r i d e c r y s t a l s being too s m a l l to give any p a t t e r n . However P d 2 + [ b e F g ] 2 ~ on h e a t i n g with f l u o r i n e at 250° and above y i e l d e d o n l y p a l l a d i u m ( I I ) h e x a f l u o r o p a l l a d a t e ( I V ) . (e) General P r o p e r t i e s . P a l l a d i u m t e t r a f l u o r i d e i s a b r i c k r e d s o l i d . I t r e a c t s v i o l e n t l y and e x o t h e r m i c a l l y with water pro-d u c i n g ozone s m e l l i n g gases. I t i s t h e r m a l l y u n s t a b l e above 350° i n vacuo when i t decomposes to Pd 2 +[PdFg"] 2~. (f ) The P r e p a r a t i o n of ( B r F 3 ) 2 P d F 4 . A suspension of p a l l a d i u m t e t r a f l u o r i d e .in bromine t r i f l u o r i d e was r e f l u x e d f o r one hour 46 at atmospheric p r e s s u r e . The t e t r a f l u o r i d e i n t e r a c t e d with the s o l v e n t and a s m a l l p a r t of the s o l i d d i s s o l v e d to y i e l d a r e d s o l u t i o n . Removal of excess s o l v e n t under vacuum y i e l d e d a r ed brown s o l i d with a pink f l u o r e s c e n c e . X-ray powder photograph showed t h i s s o l i d to be isomorphous with (BrF3)2PtF4, thereby, i d e n t i f y i n g i t as (BrF3)2PdF4. (g) The X-ray Powder Data f o r PdF4. The x-ray r e f l e x i o n s f o r p a l l a d i u m t e t r a f l u o r i d e were indexed on the b a s i s of a t e t r a -gonal u n i t c e l l w ith a = 6.585 + 0.005 ft; c = 5.835 + 0.005 A, V = 253 ft ; Z = 4; D c a i c =4.8 g/c.c. The x-ray data are given i n T able X. The f o l l o w i n g r e g u l a r i t i e s were observed i n the r e f l e x i o n s . h k l present i f h + k + 1 = 2n hkO present i f h = 2n and k = 2n Okl present i f k + 1 = 2n h h l present i f 1 = 2n and 2h + 1 = 4n The c e l l i s t h e r e f o r e body cen t e r e d , and the a p p r o p r i a t e space group i s D^-14/amd. TABLE X. C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data h k l 101 200 211 112 301 f o r PdF4 l/d2 c a l c . — ; — obs. ^obs. .052 .053 10 .092 .094 9 .145 .147 9 .164 .166 7 .239 .240 6 47 h k l c a l c . 1/d^ obs. *obs. 103 .289 .291 2 321 .330 ;333 2 312 .;350 .352 9 400 .369 .371 4 123 .380 \381 4 141 .422 .423 4 303 .472 .473 3 332 .533 .535 4 233 .564 .566 4 431, 501 .606 .609 3 413 .657 .660 3 521 .699 .697 2 512 .712 .722 2 404 .839 .839 2 503, 433 .842 .845 2 611, 334 .885 .885 3 424 .932 .930 2 253 .934 .937 2 325 1.034 1.031 3 226 1.242 1.236 2 453 1.210 1.215 3 712, 552 1.271 1.271 3 316 1.288 1.283 2 363 1.303 1.307 2 642 1.317 1.318 2 703 1.395 1.397 2 525 1.403 1.401 2 48 C. GOLD FLUORIDES (1) GOLD TRIFLUORIDE (a) P r e p a r a t i o n . The t r i f l u o r i d e was prepared a f t e r the 26 method given by Sharpe. Gold powder i n a quartz bulb, was d i s s o l v e d i n bromine t r i f l u o r i d e upon g e n t l e warming. A f t e r e v a p o r a t i o n of the s o l u t i o n at 50°, a syrupy lemon yellow mass was l e f t behind. Removal of the excess bromine t r i f l u o r i d e by vacuum d i s t i l l a t i o n gave a yellow s o l i d , presumably AuBrFg. F u r t h e r h e a t i n g of t h i s s a l t under vacuum at temperature up to 300° y i e l d e d n e a r l y pure AuF^. T h i s was f l u o r i n a t e d at 250° i n a stream of f l u o r i n e , i n order to remove any bromine present i n the s o l i d . The orange yellow samples of gold t r i -f l u o r i d e were s t o r e d under vacuum. A n a l y s i s was by p y r o h y d r o l y s i s . [\Found: F, 22.3; Au, 77.6. C a l c . f o r AuF 3: F, 22.5; Au, 7 7 . 5 % J . X-ray powder photographs were c l e a n but complex. (b) General P r o p e r t i e s . G o l d ( I I I ) f l u o r i d e was observed to decompose s l o w l y i n water to g o l d ( I I I ) hydroxide and,hydrogen f l u o r i d e as observed by Sharpe. (c) Magnetic P r o p e r t i e s . Magnetic measurements showed a n a l y -t i c a l l y pure g o l d ( I I I ) f l u o r i d e to be diamagnetic with X g = —6 o -0.13 x 10~ c.g.s. u n i t s at 293 K. (2) THE FLUOROAURATES(III), AAuF 4 (A = NO, Na, K, Rb, C s ) . (a) P r e p a r a t i o n . F l u o r o a u r a t e s ( I I I ) of sodium, potassium, rubidium and caesium were prepared by the gene r a l method of 49 Sharpe. " The r e s p e c t i v e b a s i c f l u o r i d e s and gold powder were d i s s o l v e d i n the r e q u i r e d s t o i c h i o m e t r i c r a t i o i n bromine t r i -o f l u o r i d e at 50 . Excess bromine t r i f l u o r i d e was removed under vacuum along with any other v o l a t i l e s . The pale yellow f l u o r o -a urates were s e a l e d i n quartz c o n t a i n e r s under vacuum. N i t r o s y l f l u o r o a u r a t e ^ was ob t a i n e d u s i n g excess n i t r o s y l c h l o r i d e which was condensed on to the gold powder. Bromine t r i f l u o r i d e was then d i s t i l l e d on to t h i s mixture. The r e a c -t i o n was c a r r i e d out as f o r the other f l u o r o a u r a t e s but the product was heated to ensure complete removal of N 0 B r F 4 . [ j o u n d : F, 25.4; Au, 64.9. C a l c . f o r NOAUF4: F, 25.1; Au, 65.04%3 . (b) General P r o p e r t i e s . A l l the f l u o r o a u r a t e s are pale yellow s o l i d s except the n i t r o s y l compound which i s yellow brown. They are e a s i l y h y d r o l y s e d , the ease of h y d r o l y s i s d e c r e a s i n g with i n c r e a s i n g c a t i o n s i z e . (c) Magnetic P r o p e r t i e s . A l l of the AAUF4 s a l t s (where A = NO, Na, K, Rb, Cs) were found to be diamagnetic. (c) X-ray Powder Data f o r AAUF4 S a l t s . The x-ray powder p a t t e r n s were i n a l l cases o n l y moderately complex. The sodium, potassium, n i t r o s y l and rubidium s a l t s were seen to be isomorphous. In each case the x-ray r e f l e x i o n s were indexed on the b a s i s of a t e t r a -gonal u n i t c e l l . The data f o r the caesium s a l t has not been indexed. The c e l l parameters are given i n Table XI. The observed and c a l c u l a t e d 1/d v a l u e s are given i n Tables X I I , X I I I , XIV and XV. 50 TABLE XI. The C e l l Parameters f o r A + A u F 4 S a l t s S a l t C e l l c o nstant a (8) c d > v(?0 3 NaAuF 4 5.634 10.620 337.0 KAuF 4 5.997 11.395 409.6 N0AuF 4 RbAuF 4 6.131 11.285 424.0 6.166 11.850 450.6 From c o n s i d e r a t i o n of the u n i t c e l l volumes i t was concluded t h a t the t e t r a g o n a l u n i t c o n t a i n s f o u r molecules. The f o l l o w i n g r e g u l a r i t y was noted f o r the observed x-ray r e f l e x i o n s : h k l present i f h + k + 1 = 2n. TABLE X I I . C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data f o r NaAuF4 1/d 2 h k l c a l c . obs. r o b s 002 0.0368 0.0376 8 110 0.0630 0.0641 9 112 0.0998 — -200 0.1260 — -004 0.1472 0.1463 4 202 211 0.1628 j 0.1667 J 0.1642 9 114 0.2102 — -213 0.2403 — -220 0.2520 0.2538 7 204 0.2732 0.2730 10 51 h k l c a l c . 1/cT obs. *obs 222 0.2888 0.2894 7 006 0.3150 0.3153 4 310 0.3312 0.3280 3 312 0.3518 0.3518 10 215 0.3875 0.3906 7 116 0.3942 — -224 0.3992 0.3981 7 321 0.4187 — -206 0.4572 — -323 0.4622 0.4621 9 314 0.4923 — -400 0.5040 0.5030 4 402 0,5408 0.5399 7 4.11 0.5447 — -330 0.5670 0.5670 7 226 0.5832 0.5818 7 008 0.5888 — -332 0.6033 0.6009 7 217 0.6083 — -413 0.6183 -420 0.6300 0.6289 7 325 0.6395 -' 316 0.6462 0.6452 9 118 0.6518 - - -404 0.6512 __ 52 h k l 422 424 510 512 c a l c . 0.6668 0.7772 0.8190 0.8558 1/d' obs. 0.6631 0.7735 0.8150 0.8510 obs, 7 9 3 7 TABLE X I I I . C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data f o r KAuF 4 h k l 002 110 112 200 004 202 211 114 213 220 204 222 006 310 312 l / d 2 c a l c .y. 0.0308 0.0556 0.0864 0.1112 0.1232 0.1420 0.1466 0.1788 0.2082 0.2224 0.2344 0.2532 0.2772| 0.2780J 0.3088 obs. 0.0320 0.0569 0.0877 0.1120 0.1232 0.1430 0.1829 0.2250 0.2373 0.2548 0.2805 0.3107 *obs, 8 8 10 6 4 4 4 8 2 8 53 1/d 2 h k l * c a l c . obs. Jobs 215 0.3215 116 0,3328 0.3349 7 224 0,3456 0.3481 7 321 0.3690 206 0.3884 0,3890 3 314 0.4012 0.4020 4 323 0.4206 400 0.4448 402 0.4756 — 411 0.4802 008 0,4928 226 0.4996) \ 0.5009 3 330 0.5004J 217 0.5163 332 0.5312 0.5307 2 413 0.5418 325 0.5438 118 0.5484 316 0.5552) \ 0.5561 8 420 0.5560J 404 0.5682 0.5687 2 422 0.5868 0.5881 2 54 TABLE XIV. C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data f o r NOAuF 4 l / d 2 h k l c a l c . obs. J o b s 002 0.0314 0.0318 9 110 0.0532 0.0538 9 112 0.0846 — -200 0.1064 0.1062 8 204 0.1256 0.1258 3 202 0.1378 0.1388 8 211 0.1409 — -114 0.1788 0.1811 10 213 0.2037 — -220 0.2128 0.2151 10 204 0.2320 0.2320 7 222 0.2442 0.2422 5 310 0.2660 0.2654 2 006 0.2826 — -312 0.2974 0.2973 9 215 0.3292 — -116 0.3358 0.3361 7 224 0.3384 — -321 0.3543 — -206 0.3890 — -323 314 0.3905| 0.3916 J 0.3931 9 55 1/d 2 h k l c a l c . obs. *obs 400 0.4256 0.4283 2 402 411 0.4570"! 0.4601j 0.4609 2 330 0.4788 0.4783 5 226 0.4954 — -008 0.5024 — -332 0.5102 . — -217 0.5176 — -413 0.5229 0.5206 3 420 0.5320 — -325 0.5420 — -316 0.5486 0.5511 7 118 0.5556 — -422 0.5634 TABLE XV. C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data f o r RbAuF 4  1/d 2 h k l c a l c . obs. ^-obs 002 0.0285 0.0291 10 110 0.0526 0.0528 10 112 0.0811 0,0820 10 200 0.1052 0.1062 7 004 0.1140 0.1142 5 56 h k l 202 211 114 213 220 204 222 006 310 312 116 215 224 206 314 323 400 402 411 008 226 330 217 332 413 316 420 404 l/d c a l c . 0.1337 j 0.1386 J 0.1666 0.1957 0.2104 0.2192 0.2370 0.2568 0.2630 0.2915 0.3094 J 0 . 3 0 9 8 J 0.3244 0.3620 0.3770 0.4061 0.4208 0.4493 0.4542^ 0 .4560J 0.4672 ^ 0.4734 J 0.4809 0.5025 0.5113 0.5198 0.5260 0.5348 obs. 0.1358 0.1659 0.1960 0.2131 0.2210 0.2391 0.2633 0.2916 0.3107 0.3258 0.3625 0.3768 0.4244 obs, 0.4553 0.4698 0.5016 0.5213 0.5359 4 4 7 10 5 2 10 7 5 3 9 57 (3) GOLD TETRAFLUORIDE, AuF 4 (a) F l u o r i n a t i o n of Gold T r i f l u o r i d e . Gold t r i f l u o r i d e , h e l d i n a quartz tube was heated i n a stream of f l u o r i n e . No r e a c -t i o n o c c u r r e d u n t i l 'X/ 500° when the t r i f l u o r i d e melted to g i v e a dark red v i s c o u s l i q u i d . A pale yellow sublimate condensed on the c o o l e r p a r t s of the quartz tube. In subsequent e x p e r i -ments the sublimate was caught on a c o l d f i n g e r s i t u a t e d c l o s e to the r e a c t i o n zone ("Found: F, 25.8; Au, 74.4. Required (b) F l u o r i n a t i o n of an E l e c t r i c a l l y Heated Gold Wire. Narrow gauge g o l d wire ( 3 g. of 0.030 i n . diam.) i n the form of a s p i r a l f i l a m e n t was suspended below a l i q u i d n i t r o g e n c o o l e d Pyrex s u r f a c e . P r o v i s i o n was made f o r the wire, which was connected to n i c k e l l e a d s which were brought out of the Pyrex g l a s s apparatus by way of t e f l o n compression s e a l s to be heated e l e c t r i c a l l y . Although the e l e c t r i c a l l y heated g o l d r e a c t e d r a p i d l y with f l u o r i n e to produce a pale yellow sublimate, i t proved to be i m p o s s i b l e to o b t a i n s i g n i f i c a n t q u a n t i t i e s of t h i s s o l i d . The r e a c t i o n was v i r t u a l l y u n c o n t r o l l a b l e once i n i t i a t e d and the gold r a p i d l y melted i n the hot r e a c t i o n s and formed drops of u n r e a c t i v e g o l d . (c) F l u o r i n a t i o n of I n d u c t i o n Heated Gold-Powder. Gold powder i n an alundum or n i c k e l c r u c i b l e and c o n t a i n e d i n a quartz system under a constant pressure of f l u o r i n e was heated by an i n d u c t i o n c o i l . The f l u o r i d e formed c o l l e c t e d on a l i q u i d oxygen c o o l e d f i n g e r d i r e c t l y above the c r u c i b l e . f o r AuF 4: F, 27.8; Au, 58 In these experiments the y i e l d of the f l u o r i d e was low. Massive g o l d r e s i s t s f l u o r i n a t i o n and u n f o r t u n a t e l y the i n i t i a l heat of r e a c t i o n of the powdered g o l d with f l u o r i n e was s u f -f i c i e n t to b r i n g about f u s i o n . (d) General P r o p e r t i e s of AuF 4. The pale yellow g o l d t e t r a -f l u o r i d e r e a c t s v i g o r o u s l y and e x o t h e r m i c a l l y with water pro-d u c i n g ozone s m e l l i n g gases. The s o l i d product of h y d r o l y s i s i s yellow green and c o n t a i n s some go l d metal. (e) X-ray Powder Data f o r AuF 4. In a l l cases the r e a c t i v e s o l i d m a t e r i a l r i c h e r i n f l u o r i n e than AuF 3, proved to be amorphous to x-r a y s , but s e a l e d samples were o c c a s i o n a l l y observed to y i e l d broad l i n e AuF 3 p a t t e r n s a f t e r a p e r i o d of s e v e r a l weeks. (f) The Magnetic P r o p e r t i e s of AuF 4. Magnetic measurements on a sample of AuF 4 showed i t to be h i g h l y paramagnetic with a magnetic moment LK> = 3.9 B.M. at 293°K. Temperature depen-dence of s u s c e p t i b i l i t y was not p o s s i b l e due to the very s h o r t l e n g t h of the sample. (4) FLUOROAURATES(IV) (a) Attempted P r e p a r a t i o n . Attempts to prepare complex f l u o r o a u r a t e s ( I V ) were u n s u c c e s s f u l . F l u o r i n a t i o n of 2:1 mixture of potassium f l u o r i d e and g o l d , u s i n g bromine penta-f l u o r i d e i n bromine t r i f l u o r i d e f a i l e d to y i e l d the d e s i r e d 2-[AuFgJ s a l t but gave i n s t e a d a mixture c o n t a i n i n g KAuF 4, which was i d e n t i f i e d by x-ray photography. In another e x p e r i -ment a s o l u t i o n of c h l o r i n e t r i f l u o r i d e i n i o d i n e p e n t a f l u o r i d e was employed, again without suc c e s s . 59 D. RHODIUM FLUORIDES (1) RHODIUM PENTAFLUORIDE, RhF 5 (a) P r e p a r a t i o n . Rhodium p e n t a f l u o r i d e was prepared by the a c t i o n of gaseous f l u o r i n e , of 90 p . s . i . on the t r i f l u o r i d e , at 400°. The l i d o f the monel r e a c t o r used f o r the f l u o r i n a -t i o n was c o o l e d with a i r . The dark r e d rhodium p e n t a f l u o r i d e c o l l e c t e d on the l i d . A n a l y s i s employed sodium carbonate f u s i o n as w e l l as the p y r o h y d r o l y t i c technique. ("Found: F, 47.3; Rh, 52.4. (b) Other P r e p a r a t i v e Methods. Small y i e l d s of the penta-f l u o r i d e were a l s o o b t a i n e d by the method given f o r the hexa-f l u o r i d e i n which the metal i s heated i n d u c t i v e l y i n f l u o r i n e . I t was a l s o o b t a i n e d i n low y i e l d and i n admixture with the t r i f l u o r i d e as a product of combustion o f a rhodium wire i n a f l u o r i n e atmosphere, t h i s method being e s s e n t i a l l y t h at used by Weinstock and h i s coworkers f o r the p r e p a r a t i o n of 2 platinum h e x a f l u o r i d e . (c) General P r o p e r t i e s . The p e n t a f l u o r i d e i s a dark r e d s o l i d , m.p. 95.5 + 0.5°. I t r e a c t s very v i g o r o u s l y with water producing ozone and a deep blue p r e c i p i t a t e . The penta-f l u o r i d e i s a l s o , a powerful f l u o r i n a t i n g agent. I t f l u o r i n a t e s carbon t e t r a c h l o r i d e , c h l o r i n e monofluoride being among the products. (d) Magnetic S u s c e p t i b i l i t y Data f o r RI1F5. The magnetic s u s c e p t i b i l i t y was measured f o r the temperature range Required f o r RhF =: F, 48.0; Rh 60 77-293°K. The data are given i n Table XVI. The magnetic moment at 293°K i s y t t = 2 . 9 B . M . TABLE XVI. Molar S u s c e p t i b i l i t y f o r RhF 5 Temp Temp (°K) ( i n e.g. u n i t s ) s. (°K) ( i n c.g.s. u n i t s ) 77 5895 191.3 4644 87.6 5757 210.8 4409 101 5553 226.7 4235 112.9 5299 247.4 3962 130.6 5230 267.4 3873 148.8 5054 283 .2 3726 166.5 4957 293 3669 (e) X-ray Powder Data f o r RhFg. The x-ray photograph of rhodium p e n t a f l u o r i d e was found to c l o s e l y resemble t h a t of 4 ^  .R11F5, the c r y s t a l s t r u c t u r e o f which has. been r e p o r t e d . A c c o r d i n g l y the data f o r RI1F5 was indexed on the b a s i s of a m o n o c l i n i c u n i t c e l l w i t h a = 12.38 Si, b = 9.85 c = 5.48 1; ft = 99.2°; V = 654.2 % , Z = 8, D c a l c =4.02 g/c.c. 2 A best f i t with the observed l / d v a l u e s was o b t a i n e d by o computing l / d with v a r i e d a,b,c, and j2> parameters u s i n g a program "IBFTC DATAPR" (APPENDIX I I I ) on the IBM 7040 2 computer. The observed and c a l c u l a t e d l / d v a l u e s are l i s t e d i n Table XVII. The observed s y s t e m a t i c absences i n d i c a t e d t h at RhFg i s l i k e l y to be i s o s t r u c t u r a l with RuFg. 61 TABLE XVII. C a l c u l a t e d and Observed D i f f r a c t i o n Data f o r RhF 5 h k l c a l c . obs. •^obs. 110 0.0171 0.0174 6 001 0.0342 0.0339 6 O i l , 111 0.0445 0.0459 7 201 0.0516 0.0503 9 111 0.0562 0.0564 7 220 0.0684 0.0683 10 021 0.0754 0.0754 7 121 0.0871 0.0880 2 221 0.1124 0.1136 5 321, 410 0.1219 0.1201 2 031 0.1269 0.1273 2 002 0.1368 0.1364 2 202, 231 0.1443 0.1432 2 330 0.1539 0.1538 3 401 0.1646 0.1634 4 122 0.1750 0.1754 5 520, 141 0.2112 0.1207 5 222 0.2241 0.2225 2 600, 132 0.2452 0.2456 4 530, 332 0.2631 0.2623 2 521, 322 0.2706 0.2701 3 441 0.2884 0.2892 2 62 a 1/d 2 h k l c a l c . obs. •^obs 042, 151 0.3042 0.3034 4 350, 611 0.3195 0.3193 3 251, 441 0.3292 0.3290 7 113, 123 0.3409 0.3402 7 621, 532 0.3504 0.3516 7 260, 522 0.3977 0.3958 3 161, 223 0.4076 0.4067 3 333, 451 0.4185 0.4188 2 243 0.4702 0.4699 5 642, 416 0.4880 0.4873 6 740, 741 0.4982 0.4995 2 801 0.5084 0.5086 2 114, 214 0.5451 0.5446 2 (f) I n f r a r e d spectrum: The i n f r a r e d spectrum of RhF^ showed the f o l l o w i n g a b s o r p t i o n peaks (frequency i n cm -!): 725 ( s t r o n g ) ; 675 ( s t r o n g ) ; 625 (medium s t r o n g ) ; 540-510 ( s t r o n g ) . (2) CAESIUM HEXAFLUORORHODATE(V), CsRhFg. (a) P r e p a r a t i o n . Mixture, RI1F5: CsF = 1:1, r e a c t e d i n i o d i n e p e n t a f l u o r i d e at 20° with the formation of a r e d d i s h brown pre-c i p i t a t e which was i n s o l u b l e i n excess of i o d i n e p e n t a f l u o r i d e . When t h i s excess had been removed i n a vacuum, the product was heated to a temperature not exceeding 75° f o r one hour. The red-brown caesium hex a f l u o r o r h o d a t e ( V ) was l e f t behind. 62 (b) General P r o p e r t i e s . Caesium hexafluororhodate(V) r e a c t s with water g i v i n g a blue s o l u t i o n . I t i s u n s t a b l e above 90°. (c) X-ray Powder Data f o r CsRhFg. Caesium he x a f l u o r o r h o d a t e 65 i s isomorphous and i s almost i s o d i m e n s i o n a l with CsPtFg. Accurate c e l l parameters of the rhombohedral u n i t c e l l c o u l d not be o b t a i n e d due to the poor c r y s t a l l i n i t y of the sample. 62 (b) General P r o p e r t i e s . Caesium hexafluororhodate(V) r e a c t s with water g i v i n g a blue s o l u t i o n . I t i s u n s t a b l e above 90°. (c) X-ray Powder Data f o r CsRhFg. Caesium he x a f l u o r o r h o d a t e i s isomorphous and i s almost i s o d i m e n s i o n a l with CsPtF6-Accurate c e l l parameters of the rhombohedral u n i t c e l l c o u l d not be o b t a i n e d due to the poor c r y s t a l l i n i t y of the sample. 63 E. IRIDIUM FLUORIDES (1) IRIDIUM PENTAFLUORIDE, I r F 5 (a) P r e p a r a t i o n from I r i d i u m Metal. I r i d i u m metal was heated i n a monel r e a c t o r with a s t o i c h i o m e t r i c amount of f l u o r i n e . The f l u o r i n a t i o n was c a r r i e d out at 360° f o r a p e r i o d of 24 h r s . The l i d of the monel r e a c t o r was c o o l e d with a i r d u r i n g the r e a c t i o n p e r i o d . Needle l i k e c r y s t a l s of yellow i r i d i u m p e n t a f l u o r i d e c o l l e c t e d on the l i d . A n a l y s i s f o l l o w e d sodium carbonate f u s i o n . [jFound: F, 33.3; I r , 66.3. Required f o r I r F 5 : F, 33.1; I r , 66.9%] . (b) P r e p a r a t i o n by the r e d u c t i o n of i r i d i u m h e x a f l u o r i d e  with powdered g l a s s . I r i d i u m h e x a f l u o r i d e was taken i n a s m a l l monel r e a c t o r c o n t a i n i n g powdered Pyrex g l a s s and heated to 300° f o r 12 h r s . S i l i c o n t e t r a f l u o r i d e and oxygen produced d u r i n g the r e a c t i o n were removed under vacuum. Yellow c r y s t a l s of i r i d i u m p e n t a f l u o r i d e were formed i n h i g h y i e l d on the l i d which was c o o l e d by a i r d u r i n g the reaction-. (c) General P r o p e r t i e s . I r i d i u m p e n t a f l u o r i d e e x i s t s as a yellow s o l i d which melts at 104 . 5 ° to give a dark yellow l i q u i d . Pure i r i d i u m p e n t a f l u o r i d e was handled i n dry a i r , but i n moist a i r i t fumed and r a p i d l y h y d r o l y s e d to a hydrated o x i d e . With excess of water, i t r e a c t e d v i g o r o u s l y to form a p u r p l e s o l u t i o n c o n t a i n i n g c o l l o i d a l oxide and h y d r o f l u o r i c a c i d . (d) Magnetic S u s c e p t i b i l i t y Data f o r I r F 5 . The magnetic s u s c e p t i b i l i t y of i r i d i u m p e n t a f l u o r i d e was measured over the 64 temperature range 77^296°K. The data i s t a b u l a t e d i n Table XVIII. The magnetic moment of I r F 5 i s M> = 1.31 B.M. at 293°K. TABLE XVIII. Molar S u s c e p t i b i l i t y f o r IrF5 Temp Temp 10V m (°K) ( i n c.g.s. u n i t s ) (°K) ( i n c.g.s. u n i t s ) 77 885 181.5 833 90.6 868 205.4 805 105 845 221 782 123 845 235.6 759 154.7 836 260 727 172.6 836 296 727 J (e) X-ray Powder Data f o r IvY^. Debye x-ray powder photo-graphs showed that i r i d i u m p e n t a f l u o r i d e i s isomorphous and n e a r l y i s o d i m e n s i o n a l with ruthenium p e n t a f l u o r i d e . The observed r e f l e x i o n s were indexed on a m o n o c l i n i c l a t t i c e , and the u n i t c e l l has the parameters, a = 12.5 A, b = 10.0 ft, 2 c = 5.4 A, jh = 99.8°, V = 665.4 ft , D c a l c = 5.74 g/c.c. The data i s giv e n i n Table XIX. TABLE XIX. C a l c u l a t e d and Observed X-ray D i f f r a c t i o n Data f o r I r F 5 l / d 2 h k l c a l c . obs. 110 0.171 0.174 001 0.035 0.036 obs. 4 4 1/d 2 hkl calc. obs. lobs. O i l 0.046 0.046 2 T i l 0.047 0.047 6 201 0.051 0.052 9 111 0.057 0.057 7 220 0.067 0.069 10 021 0.076 0.076 9 221 0.113 0.114 7 311 0.121 .0.122 5 031 0.127 0.128 5 131 0.139 0.138 5 420 0.146 0.145 6 Il2 0.148 0.149 10 212 0.157 0.155 9 401, 040 0.163 0.163 2 122, 510 0.179 0.179 2 511 0.185 0.185 3 430 0.197 0.197 3 520 0.206 0.204 5 141 0.210 0.209 2 521 0.215 0.215 5 222 0.230 0.226 2 600 0.237 0.235 2 422 0.246 0.245 5 332 0.261 0.261 4 440 0.269 0.272 5 66 l / d 2 h k l c a l c . obs. I o b s . 620 0.278 0.280 4 402 0.290 0.291 4 242 0.310 0.309 4 621 0.345 0.344 9 532 0.346 0.348 9 622 0.357 0.357 4 351, 720 0.365 0.364 4 260 6.394 0.394 5 632 0.408 0.407 4 800 0.422 0.421 5 622, 740 0.483 0.484 7 801 0.499 0.496 2 143 0.504 0.504 2 830, 262 0.517 0.515 2 751 0.577 0.575 2 840 0.585 0.585 2 (f) I n f r a r e d Spectrum. The i n f r a r e d spectrum of I r F g showed the f o l l o w i n g a b s o r p t i o n peaks (frequency i n c m - 1 ) : 710-700 (medium s t r o n g ) ; 670 ( s t r o n g ) ; 640 ( s t r o n g ) , 535-510 (medium s t r o n g ) . 66 1/d 2 h k l c a l c . obs. *obs. 620 0.278 0.280 4 402 0.290 0.291 4 242 0.310 0.309 4 621 0.345 0.344 9 532 0.346 0.348 9 622 0.357 0.357 4 351, 720 0.365 0.364 4 260 0.394 0.394 5 632 0.408 0.407 4 800 0.422 0.421 5 622, 740 0.483 0.484 7 801 0.499 0.496 2 143 0.504 0.504 2 830, 262 0.517 0.515 2 751 0.577 0.575 2 840 0.585 0.585 2 (f) I n f r a r e d Spectrum. The i n f r a r e d spectrum of IrF5 showed the f o l l o w i n g a b s o r p t i o n peaks (frequency i n cm" 1): 710-700 (medium s t r o n g ) ; 670 ( s t r o n g ) ; 640 ( s t r o n g ) , 535-510 (medium s t r o n g ) . SECTION I I I DISCUSSION 67 CHAPTER 1: P a l l a d i u m D i f l u o r i d e Pure p a l l a d i u m d i f l u o r i d e was prepared by B a r t l e t t and 15 Hepworth and i t s c r y s t a l s t r u c t u r e was r e p o r t e d by B a r t l e t t 37 and M a i t l a n d . The l a t t e r observed that i n p a l l a d i u m d i f l u o r i d e each p a l l a d i u m atom has a r e g u l a r octahedron of f l u o r i n e l i g a n d s about i t , the s t r u c t u r e being t h a t of r u t i l e . Such an arrange-75 ment on the b a s i s of Ligand F i e l d Theory r e q u i r e s t h a t the two dy o r b i t a l s would be f i l l e d , thus imposing on the Pd(II) 6 2 i o n a h i g h s p i n d f c d v c o n f i g u r a t i o n . A p a i r i n g of s p i n s i n t h i s c o n f i g u r a t i o n a s s o c i a t e d with non-equivalence of the two d-y o r b i t a l s would be expected to be accompanied by a gross d i s t o r t i o n of the c o o r d i n a t i o n octahedron as i n the cases of 66 67 the d i f l u o r i d e s of copper and chromium. P a l l a d i u m d i f l u o r i d e was the o n l y paramagnetic compound of d i v a l e n t p a l l a d i u m known. P r e l i m i n a r y f i n d i n g s by G i l l and Nyholm^S had shown t h a t at room temperature i t possessed a mag-n e t i c moment of 1.84 Bohr Magnetons. T h i s i s much lower than the value expected on the b a s i s of s p i n alone f o r two unpaired e l e c t r o n s . Indeed, w i t h an o r b i t a l c o n t r i b u t i o n the moment c o u l d exceed 2.83 B.M. T h i s low value was i n t e r p r e t e d as due 22 to a n t i f e r r o m a g n e t i c i n t e r a c t i o n of the Pd(II) i o n s , but there was no r e l i a b l e s u s c e p t i b i l i t y data over an a p p r e c i a b l e temperature range to support t h i s s u p p o s i t i o n . The a n t i f e r r o m a g n e t i c nature of the d i f l u o r i d e has been confirmed i n t h i s work. The s u s c e p t i b i l i t y temperature r e l a -68 t i o n s h i p i s shown i n F i g . 3. The observed Neel temperature i s 180°K. T h i s value i s c o n s i d e r a b l y h i g h e r than that observed f o r a n t i f e r r o m a g n e t i c o r d e r i n g i n the d i f l u o r i d e s of the f i r s t t r a n s i t i o n s e r i e s , the Neel p o i n t s of which are C r F 2 ( 5 3 ° K ) , ^ M n F 2 ( 7 2 ° K ) , 7 0 ' 7 1 C o F 2 ( 3 7 ° K ) , 7 1 ' 7 2 N i F 2 ( 7 8 . 5 - 8 3 ° K ) , 7 1 , 7 2 ' 7 3 and F e F 2 ( 7 9 ° K ) . 7 0 ' 7 1 ' 7 4 The h i g h e r Neel temperature i n the p a l l a d i u m f l u o r i d e i n d i c a t e s t h a t the magnetic c o u p l i n g here i s s t r o n g e r than w i t h the c o r r e s p o n d i n g compounds of the 3d 39 s e r i e s . At temperatures c l o s e to a b s o l u t e zero i n a n t i f e r r o m a g n e t i c compounds, i n t e r l a c i n g f e r r o m a g n e t i c l a t t i c e s are o r i e n t e d with s p i n s o p p o s i t e . On i n c r e a s i n g the temperature d i s o r d e r i n c r e a s e s , there being an i n c r e a s e i n the number of e l e c t r o n s which l i n e up i n the d i r e c t i o n of the f i e l d . T h i s e f f e c t i n c r e a s e s up to Neel temperature, where the o p p o s i t e alignment c h a r a c t e r i z i n g the a n t i f e r r o m a g n e t i c l a t t i c e has disappeared. F u r t h e r i n c r e a s e i n temperature, f u r t h e r randomises the o r i e n t a t i o n of the molecular magnets and the normal Curie-Weiss law r e l a t i o n s h i p i s obeyed. P a l l a d i u m d i f l u o r i d e however does not show the l a t t e r c h a r a c t e r i s t i c , the s u s c e p t i b i l i t y above the Neel tem-per a t u r e being approximately temperature independent. The temperature independent behaviour of the s u s c e p t i b i l i t y above the Neel temperature i s not yet understood. I t i s worthy of note that the o r i g i n a l p r e p a r a t i o n of PdF2 was achieved by a r e l a t i v e l y t e d i o u s s y n t h e s i s i n v o l v i n g 15 r e d u c t i o n with selenium t e t r a f l u o r i d e . The compound can now 30 J _ TEMPE RATURE - SUSCEPTIBILITY RELATION FOR Pd F. .NEEL POINT 254-2 0 . •54, to O 10. to 54. -4-FIGURE 3. 60 100 150 Ttmptraturo (»K) 200 280 l500" 70 be o b t a i n e d however by the s t r a i g h t forward i n t e r a c t i o n of bromine t r i f l u o r i d e with an equimolar mixture of p a l l a d i u m bromide and germanium d i o x i d e , to y i e l d p a l l a d i u m ( I I ) hexa-f l u o r o g e r m a n a t e ( I V ) . The p y r o l y s i s of t h i s compound at temperature i n excess of 350° y i e l d s pure c r y s t a l l i n e d i f l u o r i d e . 71 CHAPTER 2: Pa l l a d i u m T r i f l u o r i d e and R e l a t e d Compounds Nyholm and S h a r p e ^ who measured the s u s c e p t i b i l i t y of pa l l a d i u m t r i f l u o r i d e at room temperature, concluded that p a l l a d i u m t r i f l u o r i d e has a magnetic moment co r r e s p o n d i n g to a s i n g l e u n paired e l e c t r o n . T h e i r value of ^ e ± f =2.05 B.M. i s c o n s i s t e n t with one unpaired e l e c t r o n i f an o r b i t a l c o n t r i b u t i o n to the moment i s permit t e d , the c o n f i g u r a t i o n 6 1 being dg. d^ , but i t i s d i f f i c u l t to r e c o n c i l e such a value with the hig h s p i n c o n f i g u r a t i o n which possesses t h r e e unpaired e l e c t r o n s , i . e . d^ dg- . These c o n c l u s i o n s reached on the magnetic evidence however were not simply r e c o n c i l a b l e with the s t r u c t u r a l data. The c r y s t a l s t r u c t u r e i s rhombohedral, being made up of an a p p r o x i -mately hexagonal c l o s e packing of the f l u o r i n e atoms with 38 p a l l a d i u m atoms i n o c t a h e d r a l h o l e s i t e s . Each p a l l a d i u m atom i s surrounded by a n e a r l y r e g u l a r octahedron of f l u o r i n e l i g a n d s , a l l Pd-F bond le n g t h s being equal w i t h i n experimental e r r o r . Now, Ligand F i e l d Theory p r e d i c t s t h a t d^j- o r b i t a l s must be f i l l e d e q u i v a l e n t l y f o r a r e g u l a r o c t a h e d r a l c o n f i g u r a -t i o n . Any unsymmetrieal f i l l i n g of the d y o r b i t a l s would r e s u l t i n unequal i n t e r a c t i o n w i t h the s i x surrounding f l u o r i n e s and gi v e r i s e to a d i s t o r t e d octahedron. T h i s i s the phenomenon 75 u s u a l l y r e f e r r e d to as The S t a t i c Jahn T e l l e r D i s t o r t i o n . It i s s i g n i f i c a n t t h a t the p r e d i c t i o n s of t h i s theory h o l d very w e l l f o r the d i - and t r i - f l u o r i d e s as may be seen by r e f e r e n c e to Table XX. 72 TABLE XX. S t r u c t u r a l Data f o r Some D i - and T r i f l u o r i d e s Compound C r F 2 MnF 2 F e F 2 CoF 2 N i F 2 CuF 2 ZnF 2 PdF 2 F e F 3 C 0 F 3 RhF 3 IrFo (M-F) 2 A z 2.43 2.13 1.99 2.03 1.99 2.27 2.02 2.17 1.92 1.89 1.98 2.01 (M-F) 2 2 A 2 . 0 0 2.10 2.12 2.05 2.02 1.93 2.04 2.15 1.92 1.89 1.98 2.01 Magnetic Moment B.M. 4.3 5.98 5.59 4.6 2.85 1.57 1.84 2.46 diamag-n e t i c Reference 67 77, 69 77, 73 77, 78 77, 78 66, 72, 78 77 37 38 38, 40 38 38 76 As Sharpe subsequently p o i n t e d out t h i s c o u l d mean that the e l e c t r o n i c c o n f i g u r a t i o n f o r the P d ( I I I ) i o n i n PdF 3 was 5 2 6 1 40 4d^ d^- and not 4 d ^ d ^ as concluded e a r l i e r . Such a c o n f i g -u r a t i o n with t h r e e unpaired e l e c t r o n s i s however expected to show a moment i n excess of 3.87 B.M. s i n c e any o r b i t a l c o n t r i -b u t i o n would add to the s p i n c o n t r i b u t i o n . One reason f o r a low moment at room temperature c o u l d have been an a n t i f e r r o -magnetic i n t e r a c t i o n of the Pd( I I I ) i o n s . A thorough study of the temperature and f i e l d s t r e n g t h dependence of the s u s c e p t i b i l i t y was c l e a r l y necessary to r e s o l v e t h i s ambiguity. 73 The study has r e v e a l e d that p a l l a d i u m t r i f l u o r i d e i s m a g n e t i c a l l y simple, there being no evidence f o r magnetic o r d e r i n g i n the range 77-293°K. Indeed, the s u s c e p t i b i l i t y shows a near i d e a l Curie-Weiss behaviour with a Weiss constant, Q , of o n l y 28°. T h i s confirmed the s u s p i c i o n s e n t e r t a i n e d e a r l i e r t h a t p a l l a d i u m t r i f l u o r i d e i s not a Pd( I I I ) compound but i s the mixed valence compound, p a l l a d i u m ( I I ) h e x a f l u o r o -2+ —> 2 — p a l l a d a t e ( I V ) , Pd QPdFgJ . Such a f o r m u l a t i o n accounts f o r the magnetic and s t r u c t u r a l evidence. The Pd(II) i o n i s as s i g n e d the h i g h s p i n e l e c t r o n c o n f i g u r a t i o n observed i n the d i f l u o r i d e and the Pd(IV) i s given the low s p i n c o n f i g u r a -6 0 2 — t i o n d t 2 g e g observed i n the PdFg i o n (the h e x a f l u o r o p a l -23 l a d a t e s ( I V ) are dia m a g n e t i c ) . The e f f e c t i v e temperature independent magnetic moment based on the formula u n i t Pd 2Fg i s 2.88 B.M., which i s almost i d e n t i c a l with the s p i n o n l y moment. Of course the black c o l o u r of " p a l l a d i u m t r i f l u o r i d e " i s a l s o i n accor d with the Pd 2 +QPdFg"3 2~ f o r m u l a t i o n . 2+r -1 2-I t remained f o r chemical c o n f i r m a t i o n of the Pd [ P d F J 6 f o r m u l a t i o n to be found. Since p a l l a d i u m ( I I ) h e x a f l u o r o p a l -l a d a t e may be o b t a i n e d by the sequence of r e a c t i o n s : 180° o. 2-2PdBr 2 + 4BrF 3—*> 2 PdF 3.BrFg ; 2 P d F 3 B r F 3 * Pd QPdFg] + 2BrFg, t h i s i n d i c a t e s the p o s s i b l e c o e x i s t e n c e of Pd(II) and Pd(IV) i n n e u t r a l bromine t r i f l u o r i d e . Furthermore, p r e v i o u s 22 work had shown t h a t i n the presence of good f l u o r i d e i o n donors ( i . e . b a s i c c o n d i t i o n s ) bromine t r i f l u o r i d e g i v e s r i s e to Pd(IV) alone, e.g. 6 P d F 3 . B r F 3 + 1 2 S e F 4 — » 6 ( S e F 3 + ) 2 P d F g 2 - + 4 B r F 3 + B r 2 • I t t h e r e f o r e appeared probable that good f l u o r i d e 74 i o n a c c e p t o r s ( g i v i n g r i s e to a c i d c o n d i t i o n s ) would s t a b i l i z e Pd(II) i n bromine t r i f l u o r i d e . An attempt was made to prepare 2+ - i 2-a s e r i e s of p a l l a d i u m ( I I ) h e x a f l u o r o m e t a l l a t e s ( I V ) , Pd QMFgJ (where M = Pt, Ge, Sn), which were a n t i c i p a t e d to be s t r u c t u r a l l y and m a g n e t i c a l l y s i m i l a r to p a l l a d i u m ( I I ) h e x a f l u o r o p a l l a d a t e . . The l a t t e r c o n c l u s i o n was expected s i n c e t h e £ M F g l 2 ~ s p e c i e s were known to be diamagnetic i n the a l k a l i n e [_MFgl 2~ s a l t s of P t ( I V ) , Ge(IV) and Sn(IV). S u c c e s s f u l s y n t h e s i s of P d 2 + [ p t F ^ 2 ~ , 2+,- _ 2- 2+ _ 2-Pd L G e F g J a n d p d L S n F g J w a s achieved by the a d d i t i o n of bromine t r i f l u o r i d e to s t o i c h i o m e t r i c mixtures of p a l l a d i u m ( I I ) bromide and the a p p r o p r i a t e a c i d former: PdBr 2 + Ge0 2 + 2 B r F 3 >^ P d 2 + Q G e F 6 l 2 ~ + 0 2 + 2Br 2; PdBr 2 + P t ( o r S n ) B r 4 + 2 B r F 3 > P d 2 + [ P t ( o r Sn)F(j) 2 ~ + 4 B r 2 . As a n t i c i p a t e d , these s a l t s have proved to be i s o s t r u c t u r a l (see P l a t e 1) and m a g n e t i c a l l y s i m i l a r (see F i g . 4) to 2+r~ —, 2 — Pd l_PdFgJ • A s m a y b e seen from Table XXI, the h e x a f l u o -stannate by v i r t u e of i t s g r e a t e r anion s i z e has the l a r g e s t u n i t c e l l , the u n i t c e l l s of the oth e r s a l t s being c l o s e r to t h a t of Pd 2 +[_PdF 6l 2 ~ . TABLE XXI. U n i t c e l l parameters f o r Pd 2 +[MFg~] 2 ~ s a l t s . Reference 38 Present work Present work Present work S a l t Pd 2 +CPdF 63 2 ~ P d 2 + C G e F g ] 2 -P d 2 + [ p t F 6 - 3 2 -P d 2 + [ S n F g l 2 " a 5.523 + .001 A* 5.53 + .01 % 5.55 + .01 1 5.70 + 0.02 % OC 53.93 + ..01° 54.0 + .02° 54.0 + .02° 53.13 + .05° X-RAY POWDER PHOTOGRAPHS 75 76 The e f f e c t i v e magnetic moments (based on PdMFg) of these s a l t s are v i r t u a l l y temperature independent and correspond c l o s e l y to the s p i n o n l y v a l u e f o r two unpaired e l e c t r o n s , the v a l u e s at 293°K being, PdSnFg, 2.98; PdGeFg, 2.8; PdPtF g, 2.72 B.M. TABLE XXII. I n f r a r e d S p e c t r a of Some Pd 2 +[MFg~) " and A 2MF 6 Compounds Compound Frequency cm -1 K 2 P d F 6 Pd 2 +L>dFgl 2 " P d 2 + [ p t F g l 2 -P d 2 + [ G e F g l 2 ~ K 2GeFg 600 (s) 610-575 (s) 600-560 (s) 650-560 (s) 635-560 (s) 550 (w) 660 (w.s) 675-660 (w.s) 670 (m-s); 745 (w) 665 (m-s); 725 (w) * s = s t r o n g ; ms. = medium st r o n g ; w = weak; w.s. = weak sho u l d e r . The i n f r a r e d s p e c t r a of the i n v e s t i g a t e d h e x a f l u o r o m e t a l -l a t e s are t a b u l a t e d above. A l l were o b t a i n e d i n the s o l i d phase. The 610 maximum i n the i n f r a r e d spectrum of P d 2 + Q P d F g l 2 - i s c o n s i d e r e d to be the r e l a t i v e of the 0 n symmetry ~V3 funda-mental mode a b s o r p t i o n and i s c o n s i d e r e d to be i n d i c a t i v e of at l e a s t n e a r l y o c t a h e d r a l PdFg u n i t s i n the l a t t i c e . The other Pd 2 +£MFg"] 2~salts have e s s e n t i a l l y the same symmetry s i n c e the a b s o r p t i o n s p e c t r a are s i m i l a r . These o b s e r v a t i o n s are con-s i s t e n t with the x-ray powder evidence which i n d i c a t e s that these compounds are i s o s t r u c t u r a l . The x-ray s t r u c t u r e of the s o - c a l l e d 77 t r i f l u o r i d e w i l l need to be r e i n v e s t i g a t e d i n order to d e t e c t the p r e d i c t e d long bond Pd ( I I ) F g octahedra and the sh o r t bond Pd(IV)Fg o c t a h e d r a . At t h i s stage, there i s no co m p e l l i n g evidence to show that the bromine t r i f l u o r i d e adduct of p a l l a d i u m t r i f l u o r i d e i s not a Pd( I I I ) compound. A temperature s u s c e p t i b i l i t y study of t h i s compound has r e v e a l e d t h a t i t i s f r e e of magnetic o r d e r i n g s i n c e i t obeys the Curie-Weiss law i d e a l l y with a Weiss constant Q being o n l y 6°. The e f f e c t i v e magnetic moment at room temperature i s 1.81 B.M. T h i s value of magnetic moment i s c o n s i s t e n t with the presence of one unpaired e l e c t r o n s p i n and hence with the f o r m u l a t i o n s ( B r F 2 ) + P d F 4 ~ or the f l u o r i n e b r i d g e d f o r m u l a t i o n as shown: F Here the p a l l a d i u m ( I I I ) i s as s i g n e d the low s p i n c o n f i g u r a t i o n 6 1 <1Q d^. , Such a c o n f i g u r a t i o n w i l l of course be a s s o c i a t e d with 78 gross d i s t o r t i o n of a f l u o r i n e l i g a n d octahedron about the pa l l a d i u m and would give r i s e to at l e a s t or D^^ symmetry of the l i g a n d environment. A square p l a n a r PdF^~ i o n would be p o s s i b l e . I t has so f a r not proved p o s s i b l e to o b t a i n PdF^ s a l t s 23 i n bromine t r i f l u o r i d e . Attempts to prepare them y i e l d e d 22 mixtures of h e x a f l u o r o p a l l a d a t e ( I V ) and Pd(II) products. The presence of equimolar q u a n t i t i e s of Pd(II) and Pd(IV) i n n e u t r a l bromine t r i f l u o r i d e would account f o r these f i n d i n g s . I t would then be reasonable to p o s t u l a t e a f o r m u l a t i o n ( B r F 3 ) 2 P d 2 + [ P d F 6 ] 2 ~ f o r the 1:1 P d F 3 . B r F 3 adduct. T h i s f o r m u l a t i o n has the added a t t r a c t i o n of a m a g n e t i c a l l y d i l u t e 2+ l a t t i c e . The ( B r F 3 ) 2 P d i o n s would be w e l l separated from l i k e i o n s . U n f o r t u n a t e l y i t i s u n l i k e l y t h at any x-ray c r y s t a l l o g r a p h i c data w i l l be o b t a i n e d f o r the adduct. A l l specimens prepared i n the course of t h i s work were amorphous to x - r a y s . Only f a i n t broad l i n e p a t t e r n s of the P d 2 + [ P d F g ] 2 ~ were o c c a s i o n a l l y observed a g a i n s t the heavy background. Yet another f o r m u l a t i o n , g i v e n some support by the l a s t o b serva-t i o n i s t h a t the adduct would be a mixture of ( B r F g ^ P d F ^ (which i s diamagnetic) and Pd^^PdFg"] . However x-ray pat-t e r n c h a r a c t e r i s t i c of ( B r F 3 ) 2 P d F 4 was not present i n x-ray photographs of the adduct. I t i s of i n t e r e s t to i n v e s t i g a t e the reason f o r the i n s t a b i l i t y of P d ( I I I ) i n a f l u o r i n e l i g a n d environment. The present experimental r e s u l t s have shown t h a t h i g h s p i n d i v a l e n t 79 p a l l a d i u m can be a s t a b l e s t a t e f o r p a l l a d i u m where f l u o r i n e s are o c t a h e d r a l l y c o o r d i n a t e d about i t . E a r l i e r work has a l s o shown t h a t low s p i n Pd(IV) i s a s t a b l e s t a t e where f l u o r i n e s are o c t a h e d r a l l y c o o r d i n a t e d about i t . A combination of both, as observed i n P d 2 + [ P d F g l 2 ~ b e n e f i t s from the e x t r a s t a b i l i t y a s s o c i a t e d with a higher c r y s t a l f i e l d s t a b i l i z a t i o n energy (C.F.S.E. 12 Dq f o r Pd(II) and 24 Dq f o r Pd(IV).) compared to a hi g h s p i n d 7 Pd(III) (C.F.S.E. 8 Dq) i n PdF 3. With a low 7 s p i n d c o n f i g u r a t i o n f o r Pd( I I I ) a S t a t i c Jahn T e l l e r D i s -7^ t o r t i o n would occur. Presumably the l a t t i c e energy i s more f a v o u r a b l e f o r the r e g u l a r o c t a h e d r a l environments to be assoc-i a t e d with Pd(II) and Pd(IV) than with the i r r e g u l a r e n v i r o n -7 ment which would be a s s o c i a t e d w i t h the low s p i n d c o n f i g u r a t i o n of P d ( I I I ) . 80 CHAPTER 3: Gold T r i f l u o r i d e and I t s S a l t s Nyholm and Sharpe^ 0 r e p o r t e d t h a t gold t r i f l u o r i d e was weakly paramagnetic with = 0.30 x 10 6 c.g.s. and / ^ e f f = 0.5 B.M. at 293°K. They allowed however that t h i s d i d not n e c e s s a r i l y mean that Au(III) possessed unpaired e l e c t r o n s . N e v e r t h e l e s s t h i s weak paramagnetism was p u z z l i n g . T r i v a l e n t g o l d i s p s e u d o i s o e l e c t r o n i c w i t h d i p o s i t i v e g p a l l a d i u m ( c f . d ). I f the go l d were o c t a h e d r a l l y c o o r d i n a t e d , 6 2 there arose the p o s s i b i l i t y of a d f e d^ c o n f i g u r a t i o n . The paramagnetism observed by Nyholm and Sharpe was however s m a l l e r than expected f o r such a c o n f i g u r a t i o n even a l l o w i n g a n t i f e r r o -magnetic behaviour. Furthermore, with such a c o n f i g u r a t i o n AuF 3 would be expected to be isomorphous with t r i f l u o r i d e s of i r i d i u m , p a l l a d i u m and rhodium, which i t i s not. A c c o r d i n g l y a r e i n v e s t i g a t i o n of the magnetic s u s c e p t i b i l i t y of AUF3 was undertaken. I t has been observed that AUF3 prepared by decomposition of AuBrFg at 200° was paramagnetic and s t i l l c o n t a i n e d some s m a l l amounts of bromine. F l u o r i n a t i o n of t h i s m a t e r i a l at 250° under s m a l l p r e s s u r e s of f l u o r i n e gave d i a -magnetic ( Ji g = -13 x 10 c.g.s. u n i t s of 25°) a n a l y t i c a l l y g pure AuF 3. Thus Au(I I I ) i n the t r i f l u o r i d e has a low s p i n d c o n f i g u r a t i o n . T h i s would i n d i c a t e a non o c t a h e d r a l f l u o r i n e l i g a n d c o o r d i n a t i o n and a square or t e t r a g o n a l l y elongated s i x f o l d c o o r d i n a t i o n of the gold would be a p p r o p r i a t e . Thus a u n i t Au 2Fg i s a n t i c i p a t e d i n the s o l i d with approximately 81 square c o o r d i n a t i o n of the gold: Thus: F, JF Au X F ' X F However, these u n i t s may w e l l be l i n k e d by f l u o r i n e b r i d g e s , the o v e r a l l c o o r d i n a t i o n of the g o l d approximating to t e t r a -g o n a l l y elongated o c t a h e d r a l . The AAuF 4 (where A = Na, K, NO, Rb, Cs) s a l t s have, a l l been found to be diamagnetic i n t h i s work. Furthermore, the s a l t s w i t h the e x c e p t i o n of CsAuF 4 are isomorphous with KAuF 4 43 which was r e p o r t e d by Peacock to be isomorphous with K B r F 4 . NOAuF 4 has been found to be isomorphous with N0BrF 4 i n the present i n v e s t i g a t i o n . The diamagnetism of the s a l t s suggests a square c o o r d i n a t i o n and t h i s i s f u r t h e r i n d i c a t e d by i s o -morphism of the AuF 4 s a l t s with the B r F 4 ~ s a l t s i n which square c o o r d i n a t i o n of the bromine by f l u o r i n e i s a l s o a n t i c i p a t e d . The non-isomorphism of the caesium s a l t with the o t h e r s may simply be due to g r e a t e r s i z e of the caesium c a t i o n , which compared with the other c a t i o n s i s very l a r g e compared to a f l u o r i n e l i g a n d . 82 CHAPTER 4: The T e t r a f l u o r i d e s of P a l l a d i u m and Gold Broadly, the t e t r a f l u o r i d e s can be d i v i d e d i n t o two c l a s s e s : 1. The u n a s s o c i a t e d and h i g h l y v o l a t i l e compounds of SiF4 and GeF4. 2. The h i g h l y a s s o c i a t e d and r e l a t i v e l y n o n - v o l a t i l e s o l i d s l i k e SnF 4, T i F 4 and Z r F 4 . The change from h i g h l y v o l a t i l e to i n v o l a t i l e s t a t e of a g gregation cannot be a continuous change i n bond type from h i g h l y c o v a l e n t to h i g h l y i o n i c although the t r e n d from co-v a l e n t to i o n i c undoubtedly e x i s t s . Rather, the change i n v o l a t i l i t y must be a s c r i b e d to the changes i n c o o r d i n a t i n g a b i l i t y of the c e n t r a l atom. The v o l a t i l e t e t r a f l u o r i d e s are i n v a r i a b l y of T^ symmetry. Among the l e s s v o l a t i l e f l u o r -i d e s the v a r i a t i o n i n v o l a t i l i t y i n d i c a t e s c o n s i d e r a b l e s t r u c -t u r a l v a r i a t i o n . Of the f i r s t t r a n s i t i o n p e r i o d elements the t e t r a f l u o r i d e s of t i t a n i u m (b.p. 284 ) and chromium (v.p. 3 min. at 200°) are much more v o l a t i l e than t e t r a f l u o r i d e s of the second and t h i r d t r a n s i t i o n s e r i e s . 1 T h i s i n d i c a t e s that i n the f i r s t t r a n s i t i o n s e r i e s the f l u o r i n e c o o r d i n a t i o n may be as low as s i x with two unique f l u o r i n e l i g a n d s and each of the other f o u r b r i d g i n g two metal atoms as f o l l o w s : The l i b e r a t i o n of monomer would then r e q u i r e the breaking of o n l y two M-F bonds per u n i t . On the other hand, the t e t r a -81 f l u o r i d e s of z i r c o n i u m and hafnium and t h e i r s t r u c t u r a l r e l a t i v e s show a c o o r d i n a t i o n number of e i g h t f o r the metal. T h i s i s c o n s i s t e n t with t h e i r lower v o l a t i l i t y . The t e t r a -24b f l u o r i d e of i r i d i u m was anomalous i n t h a t i t possessed a low m e l t i n g p o i n t and was s u r p r i s i n g l y v o l a t i l e . T h i s was taken to i n d i c a t e a lower c o o r d i n a t i o n f o r the i r i d i u m atom 31 than that observed f o r platinum i n P t F 4 or hafnium i n 82 83 H f F 4 . ' T h i s anomaly has s i n c e been removed with the demonstration t h a t the t e t r a f l u o r i d e i s indeed a p e n t a f l u o r -i d e . I t w i l l be d i s c u s s e d under p e n t a f l u o r i d e s . 21 2 5,31 Although rhodium t e t r a f l u o r i d e and platinum t e t r a f l u o r i d e were known t h a t of p a l l a d i u m was not. Indeed the h i g h e s t b i n a r y 20 2J f l u o r i d e of p a l l a d i u m was the s o - c a l l e d t r i f l u o r i d e . ' The absence of PdF^ was f u r t h e r accentuated by the e x i s t e n c e of 5 2 h e x a f l u o r i d e s of rhodium and platinum. Furthermore, the 26 h i g h e s t f l u o r i d e of g o l d r e p o r t e d h i t h e r t o was the t r i f l u o r i d e . I t seemed probable t h a t h i g h e r f l u o r i d e of both p a l l a d i u m and g o l d should be p r e p a r a b l e . 84 Although platinum t e t r a f l u o r i d e i s produced^! with great ease under m i l d c o n d i t i o n s , the p r e p a r a t i o n of p a l l a d i u m t e t r a -f l u o r i d e r e q u i r e d s p e c i a l c o n d i t i o n s . The b r i c k r e d p a l l a d i u m t e t r a f l u o r i d e i s o b t a i n e d by the high pressure f l u o r i n a t i o n of p a l l a d i u m ( I I ) h e x a f l u o r o p a l l a d a t e ( I V ) , or p a l l a d i u m d i -f l u o r i d e at 400°. However, f l u o r i n a t i o n of the s a l t s P d 2 + [ S n F 6 l 2 ~ and P d 2 + [ P t F 6 " ] 2 ~ gave the mixed t e t r a f l u o r i d e s even at 200° and at normal p r e s s u r e s of f l u o r i n e . T h e ' t i n compound i s the most e a s i l y o x i d i s e d and i s completely f l u o r i -nated at 150° but the diamagnetic b r i c k r e d s o l i d formed at t h i s temperature g i v e s o n l y the t i n t e t r a f l u o r i d e powder d i f f r a c t i o n p a t t e r n . Presumably the c r y s t a l s of p a l l a d i u m t e t r a f l u o r i d e formed a t t h i s temperature are below the c r i t i -c a l s i z e f o r a powder p a t t e r n . Due to the great thermal s t a b i l i t y of the lower f l u o r i d e s , p a l l a d i u m t e t r a f l u o r i d e might be expected to be very r e a c t i v e . In f a c t i t i s t h e r m a l l y u n s t a b l e beyond 350°, decomposing to Pd 2 +[_PdFgT 2 ~ and f l u o r i n e . Even though i t r e a c t s with water e x o t h e r m i c a l l y to give ozone s m e l l i n g gases, i t s behaviour towards bromine t r i f l u o r i d e i s s u r p r i s i n g . I t does not o x i d i s e bromine t r i f l u o r i d e to the p e n t a f l u o r i d e , but combines with i t to form the s t a b l e adduct ( B r F g ^ P d F ^ The l a t t e r i s i s o -s t r u e t u r a l with the platinum t e t r a f l u o r i d e - b r o m i n e t r i f l u o r i d e adduct. P a l l a d i u m t e t r a f l u o r i d e (4d®j was expected to be d i a -q l magnetic l i k e platinum t e t r a f l u o r i d e , with, which i t i s Pd PdF 6 PdF 4 X-RAY POWDER PHOTOGRAPHS 85 p s e u d o - i s o e l e c t r o n i c and almost i s o s t r u c t u r a l . Samples prepared at 300° are weakly paramagnetic, the paramagnetism being a t t r i -b u table to P d 2 + | j P d F g ] 2 " . For the best c r y s t a l l i n e sample, fi 2+ 2 — X g298° = 1 * 2 3 x 1° c.g.s. u n i t s whereas X g 2 9 g o P d [PdFgl - 9.771 x 10~ 6 c . g . s . u n i t s . P alladium t e t r a f l u o r i d e i s s t r u c t u r a l l y s i m i l a r to platinum 31 t e t r a f l u o r i d e (See P l a t e 3 ) , but has an u n d i s t o r t e d t e t r a g o n a l u n i t c e l l . The t e t r a g o n a l u n i t c e l l c o n t a i n s f o u r molecules and i s s i m i l a r to the t e t r a c h l o r i d e of thorium, d e s c r i b e d by 44 Mooney . The c l o s e s i m i l a r i t y of the r e l a t i v e i n t e n s i t i e s of the powder l i n e s of p a l l a d i u m t e t r a f l u o r i d e to those of thorium t e t r a c h l o r i d e i n d i c a t e s a s i m i l a r d i s t r i b u t i o n of the heavy atoms i n the two compounds. In thorium t e t r a c h l o r i d e , each thorium atom i s c o o r d i n a t e d by e i g h t c h l o r i n e atoms arranged i n two f l a t t e n e d t e t r a h e d r a l s e t s , one at 2.46 ft, the other at 3.11 ft. The space group assi g n e d to the p a l l a d i u m 19 t e t r a f l u o r i d e u n i t c e l l from sy s t e m a t i c absences i s D,, - IA/ amd. U n f o r t u n a t e l y the low s c a t t e r i n g f a c t o r s of f l u o r i n e atoms combined with the s m a l l number of l i n e i n t e n s i t i e s a v a i l a b l e have not enabled a s i g n i f i c a n t p l a c i n g of the l i g h t atoms. The c r y s t a l s t r u c t u r e s of platinum and p a l l a d i u m t e t r a -f l u o r i d e s are c l e a r l y the f i r s t members of a new c l a s s of MF^ s t r u c t u r e s . I t i s p o s s i b l e t h a t other t e t r a f l u o r i d e s of the second and t h i r d t r a n s i t i o n s e r i e s w i l l belong to t h i s c l a s s . In p a r t i c u l a r the t e t r a f l u o r i d e s of rhodium and the as yet X-RAY POWDER PHOTOGRAPHS 86 unknown t e t r a f l u o r i d e of i r i d i u m may show s t r u c t u r a l r e l a t i o n -s h i p with t h e i r neighbours. Ruthenium t e t r a f l u o r i d e i s r e p o r t e d OA to have a "simple" powder p a t t e r n . ^ From i t s p h y s i c a l pro-p e r t i e s i t appears l i k e l y t h a t the s t r u c t u r e may be s i m i l a r to the r e c e n t l y r e p o r t e d niobium t e t r a f l u o r i d e . ^ The l a t t e r has a s i x c o o r d i n a t i o n of f l u o r i n e atoms. Osmium t e t r a f l u o r i d e i s 30a s u r p r i s i n g l y v o l a t i l e and i s not as yet s t r u c t u r a l l y c h a r -a c t e r i z e d . I t i s worthy of i n v e s t i g a t i o n . Whenever h i g h temperature f l u o r i n a t i o n of g o l d wire, gold powder or g o l d t r i f l u o r i d e was c a r r i e d out, low y i e l d s of a pale yellow s o l i d were o b t a i n e d on the c o o l e r p a r t s of the apparatus. The m a t e r i a l c o u l d be sublimed under vacuum by g e n t l y h e a t i n g to about 300°. I t r e a c t e d with extreme v i g o u r with water to l i b e r a t e ozone s m e l l i n g gases. These p r o p e r t i e s i n c o n t r a s t to those of the t r i f l u o r i d e , i n d i c a t e d t h a t i t was a f l u o r i d e of g o l d i n an o x i d a t i o n s t a t e h i g h e r than t h r e e . Great d i f f i c u l t y , however was encountered i n c h a r a c t e r i z i n g t h i s compound because of the d i f f i c u l t y of p r e p a r i n g l a r g e amounts of pure sample and i t s a n a l y s i s a l s o proved to be d i f f i c u l t by v i r t u e of the high r e a c t i v i t y . The product formed from the f l u o r i n a t i o n of e l e c t r i c a l l y heated gold wire was always a s s o c i a t e d with p a r t i c l e s of g o l d , s h a t t e r e d from the heated w i r e . The most r e l i a b l e a n a l y s i s was of a sample o b t a i n e d i n quartz by f l u o r i n a t i o n of the t r i f l u o r i d e , , T h i s i n d i c a t e d a f o r m u l a t i o n i n t e r m e d i a t e between AuF„ and AuF.. ^ I t was hoped that an i n d i c a t i o n of the v a l e n c y s t a t e c o u l d be o b t a i n e d from a magnetic study. The room temperature 87 s u s c e p t i b i l i t y measurement showed the m a t e r i a l to be h i g h l y paramagnetic ( /^294°K = B - M - ) . T h i s suggests that i f the g o l d i s i n the q u a d r i v a l e n t s t a t e , then i t must have a 7 high s p i n d c o n f i g u r a t i o n . T h i s c o u l d mean an approximately t e t r a h e d r a l c o o r d i n a t i o n of g o l d by f l u o r i n e l i g a n d s . The d 4 3 c o n f i g u r a t i o n w i l l then be the hig h s p i n d egd^2g- However the low v o l a t i l i t y of the compound can onl y be accounted f o r i n terms of a f l u o r i n e b r i d g e d l a t t i c e . A d i s t o r t e d UC1 4 44 s t r u c t u r e with f o u r c l o s e f l u o r i n e l i g a n d s (approximating to T^) and f o u r long bond f l u o r i n e l i g a n d s would be approp-r i a t e . U n f o r t u n a t e l y samples were amorphous to x-rays. However, samples of t h i s m a t e r i a l s e a l e d i n quartz c a p i l l a r i e s , a f t e r s e v e r a l weeks showed f a i n t p a t t e r n of g o l d t r i f l u o r i d e . I t i s reasonable to conclude t h a t the weak d i f f r a c t i o n p a t t e r n might have o r i g i n a t e d a f t e r the r e a c t i o n : 4AuF 4•+ SiC>2 — * 4AuF 3 + S i F 4 + 02- Although there i s need f o r f u r t h e r work on t h i s compound, the e x i s t e n c e of a higher valence of gold than three i n a b i n a r y f l u o r i d e i s c l e a r l y i n d i c a t e d . 0 3t, HF,Pd(OH)2 (rapid hydrolysis) A wafer (rapid hydrolysis) 11 bases in SeF4 , K*,Cs+-cub. Rb, (rapid hydrolysis) water trig. K 2 i 2. "^cub. Cs2 |PdF6 salts BrF, F„ hex. K 2PdF 6 cub. Cs2PdF6 cub. Rb2PdF6 I z,200-400'(h) I F2 or 0FZ at 100 psi 400° A 2PdCl 6 A 2PdCl 4 A= K+, Rb+,Cs+(d) = No +(f) = Sr 2 +,Ba 2 +(g) Hz,Pd,S0z,Iz(a) SF4(e) SeF, (c) 4 F,,400°(i) BrF.(b) Pd Br2 (or I2) acids, (BrF2)zMFs in BrF3, M - Ge, Pt (i) PdR, water (rapid hydrolysis) CsF in SeF, (reflux) (c) CsPdF , P d 2 f MF 6 2"salts water (rapid hydrolysis) (e) FIGURE 5. Pd(0H)2,HF INTERRELATIONSHIPS OF PALLADIUM FLUORIDES 89 CHAPTER 5: The P e n t a f l u o r i d e s of Rhodium and I r i d i u m  and R e l a t e d Compounds Ruff and Ascher who o b t a i n e d the t r i f l u o r i d e of rhodium by the f l u o r i n a t i o n of rhodium metal at 500-600°, had observed the f o r m a t i o n of a red brown.sublimate i n the r e a c t i o n , which 86 they a t t r i b u t e d to a h i g h e r f l u o r i d e of rhodium. However, the product was not o b t a i n e d pure enough f o r a n a l y s i s , and a 21 d e c i s i o n between RhF 4 and RhFg c o u l d not be made. Sharpe, who l a t e r prepared rhodium t e t r a f l u o r i d e concluded t h a t h i s product was i d e n t i c a l with the supposed hi g h e r f l u o r i d e of rhodium o b t a i n e d by Ruff and Ascher. The e x i s t e n c e of a p e n t a f l u o r i d e was again suspected, a f t e r the o b s e r v a t i o n of 5 Chernick, C l a a s s e n and Weinstock who noted t h a t rhodium hexa-f l u o r i d e , i n i t s r a p i d decomposition at room temperature, l i b e r a t e s h a l f a mole of f l u o r i n e f o r each mole of hexa-f l u o r i d e decomposed: RhFg;—^ RhFs + £ F 2 . The s y n t h e s i s of rhodium p e n t a f l u o r i d e has been achieved i n the present work by the h i g h pressure f l u o r i n a t i o n of rhodium t r i f l u o r i d e . A l s o the magnetic p r o p e r t i e s and s t r u c -t u r a l aspects of the new rhodium p e n t a f l u o r i d e have been s t u d i e d . Of s p e c i a l i n t e r e s t i s the r e a c t i o n of rhodium p e n t a f l u o r i d e and caesium f l u o r i d e i n the r a t i o 1:1, i n i o d i n e p e n t a f l u o r i d e , to give the f i r s t h e x a f l u o r o r h o d a t e ( V ) , caesium h e x a f l u o r o r h o d a t e ( V ) , Cs +RhFg . T h i s i s isomorphous 87 with the o t h e r CsMFg s a l t s of the noble metals. 90 The s y n t h e s i s of rhodium p e n t a f l u o r i d e confirmed a long h e l d s u s p i c i o n t h a t a p e n t a f l u o r i d e of i r i d i u m should e x i s t . Apart from the complex f l u o r i d e s (e.g. K I r F g ) , 2 4 b no simple q u i n q u i v a l e n t iridium.fluorocomppund was known. However, e a r l i e r attempts to e s t a b l i s h i r i d i u m p e n t a f l u o r i d e were u n s u c c e s s f u l . Furthermore, e a r l i e r work a l s o i n d i c a t e d that r e a c t i o n s which might have y i e l d e d the p e n t a f l u o r i d e , gave the t e t r a f l u o r i d e i n s t e a d . The p h y s i c a l p r o p e r t i e s of t h i s t e t r a f l u o r i d e however (m.-.-p. 106-107°, b . p . ^ 300°) d i f f e r e d c o n s i d e r a b l y from the t e t r a f l u o r i d e s of the n eighbouring elements. Indeed, the p r o p e r t i e s resembled those of a penta-f l u o r i d e or an oxide t e t r a f l u o r i d e . T h i s work has e s t a b l i s h e d the e x i s t e n c e of a p e n t a f l u o r i d e of i r i d i u m , a n d has proved i t s i d e n t i t y w i t h the p r e v i o u s l y r e p o r t e d t e t r a f l u o r i d e . The f l u o r i d e has been prepared i n three ways: (1) by the f l u o r i n a t i o n of i r i d i u m with the s t o i c h i o m e t r y r e q u i r e d amount of f l u o r i n e . (2) by the a c t i o n of g l a s s on the h e x a f l u o r i d e , 4 I r F g + S i 0 2 — > S i F 4 + 0 2 + 4 I r F 5 , and (3) by the a c t i o n of C l 2 on the h e x a f l u o r i d e . A l l products g i v e i d e n t i c a l x-ray photographs and melt at the same temperature. The l a s t two methods are r o u t e s given f o r the " t e t r a f l u o r i d e " . 2 4 b I r i d i u m p e n t a f l u o r i d e , i s s t r u c t u r a l l y s i m i l a r to rhodium and ruthenium p e n t a f l u o r i d e s . (See P l a t e 4) Holloway and Peacock had shown by s i n g l e - c r y s t a l x-ray d i f f r a c t i o n i n v e s t i g a t i o n t h at the s t r u c t u r e of ruthenium p e n t a f l u o r i d e c o n s i s t s of t e t r a m e r i c u n i t s , R U 4 F 2 0 , the ruthenium atoms l y i n g at the c o r n e r s of a square. The f l u o r i n e atoms are arranged about each ruthenium atom i n a d i s t o r t e d octahedron, two of the f l u o r i n e l i g a n d s being i n v o l v e d i n non l i n e a r Ru-F-Ru b r i d g -i n g bonds. I t i s b e l i e v e d , from the c l o s e s i m i l a r i t y of the x-ray powder photographs, t h a t both RhF^ and I r F ^ are i s o -s t r u c t u r a l with t h e i r ruthenium analogue and hence t h a t the s t r u c t u r a l u n i t i s f l u o r i n e b r i d g e d tetramer. I t i s a l s o observed t h a t the u n i t c e l l volume of RI1F5 i s s m a l l e r than t h a t of the h o r i z o n t a l l y p l a c e d ruthenium analogue, the v e r -t i c a l l y p l a c e d i r i d i u m p e n t a f l u o r i d e being almost i s o d i m e n s i o n a l with RuF=. The s m a l l e r u n i t c e l l volume of RhF,_ r e l a t i v e to 0 5 R U F 5 i s probably a consequence of the g r e a t e r p o l a r i z i n g power of Rh(V), the non-bonding d e l e c t r o n c o n f i g u r a t i o n of which 4 x 3 w i l l be dg. compared to Ru(V) , d ^ . The g r e a t e r n u c l e a r charge of the Rh i s not compensated f o r by the e x t r a d ^ e l e c t r o n . The magnetic p r o p e r t i e s of the p e n t a f l u o r i d e s of rhodium and i r i d i u m d i f f e r c o n s i d e r a b l y from one another, even though both r e p r e s e n t the d^ non-bonding e l e c t r o n i c systems. However i. the magnetic s u s c e p t i b i l i t y v a r i a t i o n with temperature of RI1F5 84 i s not as extreme as i n the case of ruthenium t e t r a f l u o r i d e ; 2- 88 but i s s l i g h t l y g r e a t e r than that of RuFg s a l t s . The sus-c e p t i b i l i t y dependence of RhF- might be a s s o c i a t e d with the X-RAY POWDER PHOTOGRAPHS 92 lower symmetry of the f l u o r i n e arrangement i n t h i s compound 2-compared to RuFg . In the case of I r F g , the s u s c e p t i b i l i t y i s almost independent of temperature, as expected f o r an o c t a -4 88 h e d r a l 5d system. The behaviour i s s i m i l a r to t h a t r e p o r t e d f o r h e xafluoroosmates(IV), h e x a f l u o r o i r i d a t e s ( V ) and to t h a t 89 observed i n these l a b o r a t o r i e s f o r PtFg. The p e n t a f l u o r i d e s of second and t h i r d t r a n s i t i o n s e r i e s p r e s e n t l y known are l i s t e d i n Table XXIII. When a group i s s e t out i n t h i s way resemblances are o f t e n sought v e r t i c a l l y as a consequence of the u s u a l r e l a t i o n s h i p s d i s c u s s e d with r e f e r e n c e to the P e r i o d i c System of the elements. Such r e l a t i o n s h i p s are tenuous here. Indeed d i a g o n a l r e l a t i o n -s h i p s are the r u l e , as i n d i c a t e d i n the t a b l e . I r i d i u m p e n t a f l u o r i d e e x h i b i t s s i m i l a r i t i e s i n m e l t i n g p o i n t , c o l o u r , u n i t c e l l dimensions and r e a c t i o n s to the d i a g o n a l l y p l a c e d ruthenium analogue. S i m i l a r d i a g o n a l r e l a t i o n s h i p s are a l s o found f o r the p e n t a f l u o r i d e s of rhodium and platinum. The deep r e d p e n t a f l u o r i d e s form the i s o s t r u c t u r a l and almost i s o d i m e n s i o n a l complex f l u o r i d e s of the type Cs +MFg~. Caesium h e x a f l u o r o r h o d a t e i s almost i s o d i m e n s i o n a l with caesium h e x a f l u o r o p l a t i n a t e ( V ) , (CsCl type AMFg s a l t - F i g . 6) These d i a g o n a l r e l a t i o n s h i p s are a k i n to those observed f o r the h e x a f l u o r i d e s , 9 ^ where MoFg i s much more e a s i l y reduced than WFg and more c l o s e l y resembles ReFg or OsFg i n i t s chemical r e a c t i v i t y . Furthermore PtFg e x i s t s whereas PdFg i s unknown and i s i n i t s r e a c t i v i t y a k i n to RuFg and RhFg. TABLE XXIII. Known P e n t a f l u o r i d e s of the Second and T h i r d T r a n s i t i o n S e r i e s Metals Compound m.p.; b.p.(°C) N b F 5 94 80; 235 MoF 5 67; 213.6 9 3 T C F 5 50 ; --RuF 5 86.5; 2 3 0 2 9 b RhF 5 95.5* c r y s t a l c l a s s M ( I ) 9 5 97 M ( I ) y / Q96 M(II) M ( I I ) * o a (A) 9.62 9.61 5.8 12.47 12.38 o b(A) 14.43 14.22 7.6 10.01 9.85 c(X) 5.12 5.16 16. 7 5.42 5.48 96.1 94.3 99.82 99.2 Compound T a F 5 ReF 5 O s F 5 I r F 5 P t F 5 m.p.; b.p.(°C) 94 95; 229 48; 221.3 9 3 70; 2 2 5 . 9 9 3 105;* — 8 0 3 1 ; -c r y s t a l c l a s s M ( I ) 9 5 0 4 5 M ( I I ) 4 5 MOlI) * M ( I I ) 9 8 o a (A) 9.64 12.5 o b(A) 14.45 10.0 c(X) 5.12 5.4 96.3 99.8 * Present work M = mon o c l i n i c , 0 = orthorhombic (a) NaCt TYPE , FACE CENTERED CUBIC UNIT CELL 95 Presumably the s c r e e n i n g e f f e c t of the non bonding e l e c t r o n s of the second t r a n s i t i o n s e r i e s i s much s m a l l e r than f o r the t h i r d s e r i e s elements. A g r e a t e r p o l a r i z i n g power of the cen-t r a l atom f o r a second t r a n s i t i o n s e r i e s element say Rh, than i t s t h i r d s e r i e s r e l a t i v e , I r , would account f o r the s m a l l e r molecular volume of the second s e r i e s f l u o r i d e s ( R h F 5 , 9 1 , 81.8 A*3; 5 Q 3 QQ RhFg , 99.5 A ) r e l a t i v e to the t h i r d s e r i e s analogues ( I r F 5 , Q3 93 o3 83.3 A ; Ir F g , 105.4 A ) and to the g r e a t e r o x i d i s i n g power of the former. Rh + F„ (500° (b) RhR, red hot metol;product quenched at-196°(a) BrF 3+ RhCl 3 0 3 t ,HF,Rh0 2 water (rapid hydrolysis) >500° (b) to T (i) CO (press) at70c t (Rh(CO) 2F 3) 2 volatile orange red solid HF.RhO, rapidly hydrolysed (c) inert to water K 3Rh(N0 2) 6_Juse^. K R h p + KHF 2 ( g ) 3 6 400° (h) R h l 3 + F 2 FIGURE 7. INTERRELATIONSHIPS OF RHODIUM FLUORIDES 40%HF(g) \ RhF 3,9H 20 ? Rh(H 20) 6F 3,3H 20 S03(b) (reflux) S02(b) Ir02,HSOj, HF IrF,3S0 3 H20 (b) blue solution containing cofionic Ir •Ir IrF. Clt; glass ol 350° (h) Ir F= • F2 at 380'excess Jr(h) -F2ot 300° in (a) fluorite or (b) alumina Ir SeF4 + CsF (c)-NO (I'D (h) —30' SF, or SeF4 (c) NO+IrF; excess NO 60'(b) S(Se)^,IrF5 200' (c) S(Se)F4,2IrF5 T o' x/ A B r BrF. - 3 5 \A(Br0 3 ) 2 W f f , Cs + No+ Li+ Ag+ Cs + " Rb+ K + Bo + t ton exchange * base (el colloidal IrO, H,0, (d,f) IrF6 salts H2° (d) K 3 Ir(N0 2 ) 6 + KHF 2 fusion (g) I \t > -S»-K\ Na* NH +, K+,Cs+, Bo+ 4 (N02+)2IrF62' SF4(350-400')(b) glasstSiOz—SiFi+ytb) ol 430' Ir(*F 2?)-decomp. absent (b) i iflrF, f 01250' L (N0+)2IrF62" heated in vacuo (b) IrF, (NO+2)2IrF52' 250° |(NO+)2IrF2" ? IrF62"solts FIGURE.8. inert to hydrolysis INTERRELATIONSHIPS OF IRIDIUM ID - J FLUORIDES 98 TABLE XXIV. 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B a r t l e t t , 1st Noranda L e c t u r e , Chemistry i n Canada, August 1963, p. 33-40. 91. J . H. Holloway, P. R. Rao and N. B a r t l e t t , Chem. Comm. 1965, 14, 306. 92. N. B a r t l e t t and P. R. Rao, Chem. Comm., 1965, 12, 252. 93. G. H. Cady and G. B. Hargreaves, J . Chem. S o c , 1961, 1565. 94. F. F a i r b r o t h e r and W. C. F r i t h , J . Chem. S o c , 1951, 3051; F. F a i r b r o t h e r , W. C. F r i t h , and A. A. Woolf, J . Chem. S o c , 1954, 1031. 95. A. J , Edwards, J . Chem. S o c , 1964, 3714. 96. A. J . Edwards, D. H u g i l l , and R. D. Peacock, C i t e d i n Proc. Chem. S o c , 1963, 205. 105 97. A. J . Edwards, R. D. Peacock, and R. W. H. Small, J . Chem, Soc. , 1962, 4486. 98. N. B a r t l e t t and M. Akhtar, Unpublished r e s u l t s . APPENDICES APPENDIX I "A"^T?OTi'Rl\~M~FUR^ 1/D»»2 AND NELSON RILEY EXTRAPOLATION FUNCTION , • • $JOB 15104 P R RAO TTBTTC I'NUEXX ; : : — : 44 BN = 0. '  CN=0. STPW; : : ; S3P=0. * • • - C CALC OF BEAM STOP CENTRE BPA=AV(X1+X2/2) O Z DATA CARD WITH X1 = X2 = 0 SIGNALS END OF DATA '. " I READ(5t30)Xl»X2 . " • • 30 FORMAT(2F10.3) gp_ (xi+X2 ) /2. '. ' SBP = SBP+BP , • IF(BP.EQ.O.)G0 TO 3 BN=BN+1• : : : GO TO 1 . " 2 .  3 BPA=SBP/BN "C CALC OF COLLIMATOR CENTRE CPA=AV(X1+X2)/2 : c DATA CARD WITH X1=X2=0. SIGNALS END OF DATA 1 4 READ(5»30)X1*X2 GP=(Xl+X2)/2. •• SCP=SCP+CP /. IF(CP.EO.O.)G0 TO 5 . . CN=CN+1. GO TO 4 5 CPA=SCP/CN - > WRltE(6.75) >-• • o 75 FORMAT(IX•10H XI ,20H 1HKL ,20H 1/D*D »30H 2THETA » 20H D NRFN // 2//> C FACTOR TO CONVERT ARC TO ANGLE ANGLE=3.1414/(CPA-BPA) IF(ANGLE.LT.O.)GO TO 7 -GO TQ 13 7 ANGLE=-ANGLE — C CALC OF 2THETA.DCORR*1/D*D C IF X FOR" ALPHA 1 ADD 100 TO X VALUE c IF X FOR ALPHA2» ADD 200 TO X VALUE c X1=0 SIGNALS END OF DATA + NO OTHER SET c Xl=999 SIGNALS END OF DATA + ANOTHER SET FOLLOWING 13 READ(5*2)XI 2 FORMAT(F10.3) IF(X1.EQ.O.)G0 TO 17 ' IFIX1.EQ.999.)GO TO 70 IF(X1.GT.200.)GO TO 14 IF(XI.GT.100.)GO TO 15 O oo AMBDA=0.7709 GO TO 16 ^ Xl=Xl-200. AMBDA=0.77217 GO TO 16 15 X1=X1-100. AMBDA=0.77025 GO TO 16 ~ . • ' 16 X2=X1-BPA THETA2=X2*ANGLE IF(THETA2.LT.0.)G0 TO 20 ) GO TO 21 20 THETA2=-THETA2 2 1 THETA=THETA2/2. / .) CTHETA=COS(THETA) '1 STHETA=SIN(THETA) . _ ... XTHETA=1./STHETA DHKL=AMBDA*XTHETA DINSQ=1./(DHKL*DHKL) o CO XNRFN=0.5*((CTHETA*CTHETA/STHETA)+(CTHETA*CTHETA/THETA)) THETA2=360./6.2828*THETA2 -WRITE(6»18)Xl»THETA2»DHKL,DINSQ»XNRFN 18 FORMAT(1X.F10.3.10H .F10.3*10H »F10.5»10H 1 »F10.6»20H »F10.3/) ,T I 12 GO TO 13 J l ho 9 70 CALL SKIP TO (1) GO TO 44 8 7 17 STOP 5 * 4 3 END APPENDIX II TTTT^TRSTCTtf^FD"^^ OF MAGNETIC SUSCEPT i T R T T Y DATA $JOB 15104 P R RAO SIBFTC APPROX C FORTRAN FOUR CONVERSION OF STRAIGHT LINE APPROXIMATION C ESTIMATION OF PARAMETERS FOR A STRAIGHT-LINE APPROXIMATION S3-6 1 • C LET N = NUMBER OF OBSERVATIONS S3-6 3 C LET X = INDEPENDENT VARIABLE S3-6 4 C LET Y = DEPENDENT VARIABLE S3-6 5 o C THIS PROGRAM FITS LINE TO 1/MAGS VS TEMP C LET Y(J) BE MAGS NOT 1/MAGS C LET X(J) BE TEMP 14 SX = 0. S3-6 6 SY = 0, S3-6 7 SXX = o « S3-6 8 SXY = 0 . S3-6 9 SYY = 0 . S3-6 10 J = 0 READ(5»1)N»AX»AY 1 FORMAT(I6»2X»A4»2X»A4) S3-6 12 DIMENSIONX.100)»Y(100) DO 2 I = 1»N S3-6 13 J=J+1 READ(5»3)X(J)»Y(J) 3 FORMAT(F7.0*F7.0) Y(J)=1./Y(J) SX = SX + X(J) SY = SY + Y(J) SXX=SXX+X(J)*X(J) t—1 5XY = 5XY + Xt J)*Y'( J) 2 SYY=SYY+Y(J)*Y(J) READ(5*20)TEST 20 FORMAT(A3) CALL SETHOL(CHECK•3HEND) , S3-6 22 IF(TEST-CHECK)11.12»11 11 WRITE(6»13) 13 FORMAT (51H WRONG NUMBER OF DATA CARDS OR LAST DATA~ CARD NOT » 1 32HFOLLOWED BY AN END-OF-DATA CARD ) STOP S3-6 27 12 FN = N S3-6 28 DN = l./FN S3-6 29 AVX = SX*DN S3-6 30 AVY = SY*DN S3-6 31 CALL SKIP TO (1) WRITE(6»4)AX,AVX»AY>AVY 4 FORMAT(16H MEAN VALUE OF A4,3H DNN = l./(FN - 1.) = E13.6/15X»A4,3H = E13.6) S3-6 35 S = SXX - SX*AVX S3-6 36 t— to COVX = S*DNN - S3-6 37 COVY = (SYY - SY*AVY)*DNN S3-6 38 COVXY = (SXY - SX*AVY)*DNN S3-6 39 STDX=SQRT(COVX) STDY=SQRT(COVY) WRITE<6»5)AX»STDX»AY»5TDY 5 FORMAT(//23H STANDARD DEVIATION 1 ) OF A4.3H = E13.6/22X.A4.3H = • E13.6 CORR = COVXY/(STDX*STDY> S3-6 44 W^rTE(6»6)AX,AY,CORR 6 FORMAT(//21H CORRELATION BETWEEN A4 >4HAND A4,3H = F10.8) A = COVXY/COVX S3-6 47 WRITE(6t7)A 7 FORMAT<//32H SLOPE OF REGRESSION LINE = E13.6) B = AVY - A*AVX S3-6 50 WRITE(6*8)B 8 FORMAT(32H INTERCEPT OF REGRESSION LINE = E13.6) R=SQRT((FN-1.)*(C0VY-A*A*C0VX)/(FN-2.)) WRITE(6»9)R 9 FORMAT(32H STANDARD ERROR OF ESTIMATE = E13.6) M M W SI=R*SQRT(DN+AVX*AVX/S). SS = R*SORT( l./S) WRITE(6ilO)SS»SI 10 FORMAT(31H CONFIDENCE INTERVAL PARAMETERS/2IX10HSLOPE = E13.6/ 121X10HINTERCEPT E13.6) • , WRITE(6»22) 22 FORMAT(////115H TEMP SUSC.(OBS) SUSC(CALC) 1 DEVIATION (CGS*10E-6) 1/TEMP l/SUSC("bBS) (1/CGS)) N = FN J = 0 D042I=1*N J = J + 1 YCALC=A*X(J)+B . SCALC=1000000./YCALC • SOBSV=1000000*/Y(J) SDEVI=SOBSV-SCALC TINV=1./X(J) WRITE(6*33)X(J)»SOBSV•SCALC*SDEVI•TINV*YI J) • 33 FORMAT(F10.2,8H »F10.2»9H »Fl0.2»9H »F10.2» t-1 M 116H »F10.5»2H »F10.2) 42 CONTINUE WRITE(6»44) . 44 FORMAT (////28H TEMP SUSC (CALC)/./.) TEMP = 60. ,• ' ' • D052I=1»12 — TEMP=TEMP+20. YCALC = A*TEMP+B 8 7 SCALC=1000000./YCALC 5 4 3 WRITE(6*55)TEMP*SCALC 55 FORMAT(F10.2,8H »F10.2) 52 CONTINUE '  GO TO 14 S3-6 61 E7TD ' -f S3~6 62 / SENTRY ' - • 14 TEMP MAGS -APPENDIX-TIT A Program f o r the C a l c u l a t i o n of 1/d, , , from U n i t C e l l Parameters $JOB 15104 P.R.RAO $ 1 lMt 15 , . SIBFTC DATAPR 988 READ 989» I PR It I0UT1 989 FORMAT (12.12) REWIND I0UT1 - ' r- : GO TO (90»99)• IPR1 o 90 READ 80» WAVE»A1*A2»A3»CSA1.CSA2*CSA3*SNA2»PHI0»FL1M 80 FORMAT(F5.4»4X»F6.6*F6.6,F6.6*2X*F7.5 *F7.5,F7.5•F7.5•2X.F7.3»F3.2) J R1=WAVE*A1*SNA2 R2=WAVE*A2*(CSA3-CSA1*CSA2)/SNA2 R3=WAVE*A2*SQRT (1.-CSAl**2-CSA2*»2-CSA3#*2+2.#CSA1*CSA2*CSA3) 1 /SNA2 -R4=WAVE*A1*CSA2 .  R5=WAVE*A2*CSA1 R6=WAVE*A3 FOVLS = 4.0/(WAVE**2) 81 READ 81» LSTRT.LNEG1»LNEG2»L»M»N»KIN.JIN.II»JJ.KK FORMAT (I2»I2»I2»I2»I2»I2»7X»I2»I2*6X»I1»11*11) JSIGN=1 69 KS1GN=1 , 70 DO 1 IP=LSTRT.50.L FI=IP-1 ; ....—~~ • • - \ 71 DO 2 JP=1»50.M IF (JSIGN) 52.53.53 • •••• . 1 72 DO 3 KP=1.50.N 1— - IF (KSIGN) 56.59.59 73 X1=R1*FKD+ R2*FJ + 0.0000001 X2=R3*FJ - " X3=R4*FKD+ R5*FJ + R6*FI DIMENSION LFI(3) -SINSQ=0.25*(X1»*2 + X2**2 + X3**2) OOVDS = FOVLS * SINSQ IF (SINSQ-FL1M) 8.9.9 9 IF (FKD) 2.10.2 10 . IF (FJ) 1.20.1 4 8 TW0TH=114.59156*ATAN(SQRT (SINSQ/(1.-SINSQ))) CHI=57.29578*ATAN(X3/SQRT (Xl**2 + X2**2)> PHI=57.29578*ATAN(X2/X1) +PHIO I"F^X1T~31DT3TT3~1 30 PHI=PHI + 180. GO TO 35 31 IF (X2) 32.35.35 32 PHI=PHI + 360. 35 LFI(1)=FKD i — 00 LFI(2)=FJ LFI(3)=FI IF (PHI-360.) 3.37.37 37 PHI=PHI-360. 3 PUNCH 2011. LFI(I I ) . L F I ( J J ) .LFI(KK).OOVDS 2011 FORMAT (10X.3I3.27X.F8.3) 2 CONTINUE 1 CONTINUE -20 IF (KSIGN) 21.22.22 22 KSIGN = KIN 3 IF (KSIGN) 91,21.21 91 LSTRT=LNEG1 GO TO 70 21 IF (JSIGN) 23*24,24 / 24 JSIGN=JIN -IF (JSIGN) 92.25.25 92 LSTRT=LNEG2 GO TO .70 _ 23 IF (KSIGN) 69.25,25 M M CO 25 PRINT 26 26 FORMAT (1X.14HSTARTING SORT) GO TO 100 0 52 FJ =-JP+l GO TO 72 53 FJ = JP-1 GO TO 72 56 FKD=-KP+1 — GO TO 73 59 FKD= KP-1 GO TO 73 C 100 LIBRARY PROGRAM FOR SORTING DATA (IBSRT) C WITH FINAL OUTPUT ON PRINTER 100 GO TO 988  99 READ 101, WAVE,AA»BB,CC»CSA»CSB»CSG•NCURV»IFILE TOT FORMAT (F5 . 4 » 4 X,F6.6»F6.6»F6.6»2X»F7 . 5»F7.5»F7.5»9X,I2»2X, 1 2 ) WAVE2=.WAVE»*2 • ' _ _ _ _ _ AHH=0.25 * WAVE2 * AA**2 A~KT=~0.25 * WAVE2~*~~Eft*~*2 : :  ALL=0.25 * WAVE2 * CC*»2 ' ^ AHL=0.50 * WAVE2 * AA*CC*CSB AHK.=0.50 * WAVE2 * AA*BB*CSG '. : '. " AKL = 0.50 * WAVE2 * BB*CC»CSA  DIMENSION FCURV(8), F 0 ( 8 ) , P ( 8 ) , F(8»14) •_• DO 200 I=1,NCURV 200 READ 201, P ( I ) , FO ( I ) , (F(I,J),J=1,14) •  201 FORMAT (16F5.3) DO 4 0 0 1 = 1 , 8 ™ ; " 47J0" FCURV( I ) =0• ONOLS = 1./WAVE2 C ROUTINE FOR WINDING OUTPUT TAPE TO PROPER FILE 1 ASSIGN 253 TO IENDF CALL EOF (IOUT1.IENDF) • * NFILE = IFILE 254 IF (NFILE - 1) 102.102.252 252 READ (IOUT1) II.IGPEN.SSOLS.FH.FK.FL.FOBS.FOBS2• (FCURv7l),I=1.8) GO TO 252 .1— • to I—" 253 NFILE = NFILE - 1 GO TO 254 102 READ 103.11.IGPEN.FH.FK.FL.FINT.VBS.S1NSM -103 FORMAT (I2.1X.I2.5X.F3.0.F3.0.F3.0.2X.F5.0.4X.F5 IF (II) 300.301.300 .2.5X.F5.5) I 301 IF (IGPEN) 300.302.300 i 2 i i 300 SSOLS=0« 10 9 FREL = 0. ' ••• -8 l7 6 FSQR=0. 5 4 3 DO 303 I=1.NCURV .—_ 303 FCURV(I)=0. GO TO 105 302 FS1N2 = AHH*FH**2 + AKK*FK**2 + ALL*FL**2 + AHL*FH*FL + AHK*FH*FK + 1 AKL*FK*FL IF (FS1N2 -1.) 104*104*102 104 RCL0R=2.*SQRT ((1.-FS1N2)*(FS1N2-S1NSM))/(1.-2.*FS1N2+2.*FS1N2**2) FSQR = FINT * RCLOR * VBS : FREL = SORT (FSQR) SSOLS = FS1N2 * ONOLS STOTS -^ -SUFfT TSTOXST IF (STOLS - 0.1) 203*204*204 203 DO 0 202 I=1»NCURV 202 FCURV(I) = F0(I)/EXP (P(I)*SS0LS) GO TO 105 204 IF (STOLS - 1.0) 205,206*206 205 KO = 1 207 Kl = KO + 1 ^ -E l = K l F l = 0.1*E1 — _ IF (STOLS - F l ) 40,41,41 41 KO = KO + 1 GO TO 207 40 EO = KO • j FO = 0.1*E0 K2 = KO + 2 K3 = KO + 3 RANGE = STOLS - FO DO 402 I=1,NCURV i —1 ts3 CO 402 FCURV(I) = F(I,K0) + (F(I,K1)-F(I,K0))*RANGE*10» + 50.* 1 (F{I,K2)-2.*F(I,K1)+F(I,K0))*RANGE**2 + 166.667* 2 (F(I,K3)-3.*F(I,K2)+3.*F(I,K1)-F(I,K0))*RANGE**3 r GO TO 105 206 KLOW =10 209 KHIGH= KLOW + 1 EH IGH= KHIGH FHIGH= 0.1 * EHIGH -IF (STOLS - FHIGH) 42,43,43 43 KLOW = KLOW + 1 GO TO 209 42 DO 502 I=1»NCURV 502 FCURV(I) = F(ItKHIGH) + ( F ( I » K L O W ) - F ( I » K H I G H ) )*(FHIGH-STOLS)* 10• 105 PRINT 2013, I I , I G P E N , S 5 0 L S » F H , F K , F L , F R E L » F S Q R , (FCURV(I),1 = 1 ,8) 2013 FORMAT ( 1 X , I 2 » 1 X » I 2 , 1 X , F 7 . 4 , 2 X , 3 F 5 . 0 » 2 X , F 6 . 1 , 2 X , F 6 . 0 , 7 ( F 6 . 3 , 1 X ) , 1 F6.3) 106 IF ( I I ) 198,102,198 198 GO TO .99 ! END t-1 to \ ' ? SENTRY 0102 ! 15418 .2363 .2363 .2363 -.375 -.375 -.375 .927 050 \ f 1 2 1 1 1 -1 123 ;I 12 11 ?10 9 8 5 - 4 3..., .. 

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