B o t h m o l y b d e n u m ( V I ) a n d t u n g s t e n ( V I ) fluorides a r e readily p r e p a r e d a n d h a v e b e e n well characterized. D i r e c t c o m b i n a t i o n of t h e elements, using either flow or s t a t i c t e c h n i q u e s , is a satisfactory pre
p a r a t i o n . N a F , a c t i n g as a ' ' g e t t e r " enables t h e p r e p a r a t i o n s t o be carried o u t in glass a p p a r a t u s (Ruff a n d Ascher, 1931; B e r n h a r d t et al, 1955; B a r b e r a n d C a d y , 1956; O'Donnell, 1956; Alyea et al, 1957;
I w a s a k i et al, 1962). O t h e r p r e p a r a t i v e r o u t e s involve fluorination of t h e h e x a v a l e n t oxides w i t h b r o m i n e trifluoride (Nikolaev a n d Sukhover-k h o v , 1957), s u l p h u r tetrafluoride (Smith, 1959; O p p e g a r d et al, 1960), or h y d r o g e n fluoride (Nikolaev, 1954). F l u o r i n a t i o n of t h e m e t a l s w i t h chlorine trifluoride or b r o m i n e trifluoride are useful r o u t e s t o t h e h e x a fluorides. H o w e v e r , in t h e l a t t e r m e t h o d it is difficult t o purify t h e p r o d u c t from t h e b r o m i n e trifluoride (Cox et al, 1956; Clifford et al, 1957;
Nikolaev et al, 1958; N i k o l a e v a n d Opalovskii, 1959a). Finally, t u n g s t e n h e x a c a r b o n y l h a s been fluorinated w i t h r h e n i u m hexafluoride a n d iodine pentafluoride ( H a r g r e a v e s a n d P e a c o c k , 1958a, 1960). T h e m i x e d halide WF5CI h a s r e c e n t l y b e e n p r e p a r e d as a yellow solid (m.p. —33-7°) b y t h e e x c h a n g e r e a c t i o n b e t w e e n W F g a n d TiCl4. T h e v a p o u r is m o n o m e r i c a n d t h e c o m p o u n d dissociates before boiling (Cohen et al, 1965).
Of t h e chlorides only t u n g s t e n hexachloride exists a n d is formed b y chlorination of t h e m e t a l w i t h either chlorine gas ( K e t e l a a r et al, 1943;
K o r s h u n o v a n d Gol'den, 1961) or s u l p h u r monochloride ( F u n k et al, 1957). O t h e r p r e p a r a t i v e r o u t e s involve t h e chlorination of t u n g s t e n (VI) oxide or sulphide w i t h chlorine, s u l p h u r monochloride, p h o s p h o r u s
TABLE XXI. Molybdenum(VI) and tungsten(VI) halides ComFormation data Melting Boiling Solid Solid Specific S"" Colour pound (e.u.) point point transition heat (C„) (e.u.) (kcal (kcal (e.u.) (°C) (°C) (°C) (cal mole~^ mole~^) mole-^) deg-i) MoFe 388-6(1) 361-2(1) 72.1(g)e 22-5, 17-4d,e,f 34-35d.e — 9-6, -8-7d>g 28-4i>J.k 80-81i»J.i^ white 372-4(g)^.c 350-8(g)^.c 20-6d»e WFe 422(l)i> 397(l)i> 22d,e 2-3 2-0 (413-2 mm)d»e 17-1, 17-5d>e — 8-2d,ii 28-5i.J 81-81.3 white WCle (a) 163-1 (a) 107 20-4, 282-284o,P 337* 227, 230 blue- {β) 157 74 {β) 94in 24-9°»o (a->i3) black 96.9a,l,m 93 New transition 168-169°?o»P WBre 114Q 38 95 309^ blue- 66 black Values underlined are estimated (cf. a Brewer aZ. (1950). * Myers and Brady (1960). c Settle aZ. (1961). d Cady and Hargreaves (1961a). e Ruff and Ascher (1931). « O'Donnell (1956).
Brewer et al., 1950). K Brady aZ. (1960). ^ Barber and Cady (1956). i Gaunt (1953). 3 Sundaram (1962). k Claassen aZ. (1962). 1 Shchukarev et al. (1958c).
^ Shchukarev et al. (1960a). ^ Shchukarev and Novikov (1956). oKetelaar et al. (1943). Ρ Stevenson et al. (1964). <i Shchukarev and Kokovin (1960). Γ Shchukarev and Novikov (1959).
Α
ι
Α cl Ο§
•-3 to -α278 J. Ε. FERGUSSON
p e n t a c h l o r i d e (Gmelin, 1933), carbonylchloride, t h i o n y l chloride, h y d r o gen chloride (Horizons, 1959), or carbon t e t r a c h l o r i d e (Bardaivil et al.,
1964; K n o x et al., 1957; S h c h u k a r e v et al., 1958b), u n d e r differing e x p e r i m e n t a l conditions. Of t h e s e m e t h o d s , direct c o m b i n a t i o n of t h e elements or chlorination using carbon t e t r a c h l o r i d e are p r o b a b l y t h e best.
B r o m i n a t i o n of either t u n g s t e n m e t a l or t u n g s t e n h e x a c a r b o n y l gives t h e h e x a b r o m i d e (Gmelin, 1933; S h c h u k a r e v a n d N o v i k o v , 1959;
S h c h u k a r e v a n d K a k o v i n , 1960), t h e s t u d y of which h a s b e e n neglected in r e c e n t y e a r s .
T h e hexafluoro a n d hexachloro c o m p o u n d s h a v e b e e n s t u d i e d e x t e n sively, especially t h e i r t h e r m o d y n a m i c properties, w h i c h are listed in T a b l e X X I . T h e W — C l b o n d s t r e n g t h is 73-7 kcal m o l e- i (exptl), a little higher t h a n t h e calculated v a l u e of 68 kcal mole-^ (Allen, 1956, 1957). T h e c o m p o u n d s are m o n o m e r i c in t h e gaseous s t a t e .
T h e h e x a h a l i d e s a r e solids a n d r a p i d l y h y d r o l y s e t o give oxyhalides (Nikolaev et al., 1960). T h e fluorides a n d t h e chloride dissolve in organic solvents, generally w i t h r e a c t i o n , in w h i c h t h e m e t a l is c o n v e r t e d t o t h e p e n t a v a l e n t s t a t e . This occurs m o s t readily for t h e hexachloride. I n benzene W F ^ is said t o form a complex WFg.CgHg (Priest a n d S c h u m b , 1948). " C F g " from (CF3)3PF2 reduces t h e m o l y b d e n u m c o m p o u n d (Mahler, 1963). I t fluorinates t h e trihalides of g r o u p V b , forming M0CI5 in t h e process (O'Donnell a n d S t e w a r t , 1962). T h e b e h a v i o u r of t u n g s t e n hexachloride in oxygen-free organic solvents a p p e a r s t o be one of dis
sociation, WClg ^ WCI5 + I CI2 a n d n o t t h e formation of oxychlorides ( W a r d l a w a n d W e b b , 1930; Shirokshina a n d S u i k o v s k a y a , 1960; J . E . Fergusson, B . H . R o b i n s o n a n d C. J . Wilkins, u n p u b l i s h e d ) . I n b e n z e n e a n d carbon t e t r a c h l o r i d e t h e m a g n e t i s m of t h e species in solution, originally d i a m a g n e t i c , rises t o 1-62 a n d 0-97 Β respectively, a n d complexes WCI5.2L h a v e been isolated (see above). H o w e v e r , if oxygen-containing solvents are used oxychlorides are formed. A d d u c t s
TABLE X X I I . T h e r e a c t i o n o f W C l e w i t h a m i n e s
A m i n e P r o d u c t R e m a r k s References
P r i m a r y W C l 2 ( N H R ) 4 diamagnetic 1
P r i m a r y [W(amine)6]Cl6 probably solvolytic 2
(aromatic) products
Secondary 1:1 a d d u c t followed paramagnetic 1
b y reduction t o {d^ config.)
[NR^H^JaWCIe
Tertiary as for secondary 1
(in excess) a m i n e
1 , Brisdon et al. ( 1 9 6 2 ) ; 2 , Prasad a n d Krishnaiah ( 1 9 6 0 ) .
H A L I D E C H E M I S T R Y O F C H R O M I U M , M O L Y B D E N U M A N D T U N G S T E N 279
Mode S y m m e t r y A c t i v i t y MoFe W F e
R 741 7 7 2
V2 R 6 4 5 6 7 2
VQ Txu i.r. 741 7 1 2
Vi i.r. 2 6 0 2 5 8
V5 Tu R 3 2 2 3 1 6
v% I n a c t i v e (234) (211)
a Force c o n s t a n t s for A— F stretch are in t h e ranges 4 - 9 - 5 · 1 a n d 5 - 1 - 5 - 4 χ 10^ d y n e s c m- i for m o l y b d e n u m a n d t u n g s t e n respectively (Gaunt, 1 9 5 4 ; V e n k a t e s w a r l u a n d Sundaram, 1956; Pistorius, 1 9 5 8 ; Claassen, 1 9 5 9 ; L i n n e t t a n d Simpson, 1 9 5 9 ; Meisingseth a n d Cyvin, 1 9 6 2 ; N a g a r a j a n , 1 9 6 3 ; K i m u r a a n d K i m u r a , 1963).
E l e c t r o n diffraction studies d e m o n s t r a t e o c t a h e d r a l s y m m e t r y for MoFe, W F e a n d WCle ( W — F - 1-826 Â, W — C l = 2 - 2 6 Â). T h e crystal s t r u c t u r e of t h e chloride confirms t h i s (W—CI = 2·24 Â), a n d in t h e solid t h e chlorine a t o m s h a v e a deformed h e x a g o n a l close p a c k e d a r r a n g e m e n t ( B r a u n e a n d P i n n o w , 1937; E w e n s a n d Lister, 1938;
K e t e l a a r a n d O o s t e r h a u t , 1943; G l a u b e r a n d S c h o m a k e r , 1953; W e i n stock a n d M a l m , 1958).
T h e electronic a b s o r p t i o n s p e c t r u m of t u n g s t e n hexachloride in car
b o n t e t r a c h l o r i d e is p r o b a b l y complicated b y t h e dissociation w h i c h occurs in t h a t solvent (Jorgensen, 1959). A low q u a d r u p o l e coupling c o n s t a n t for t h e hexachloride m a y be r e l a t e d t o some 7r-bonding i n t h e molecule ( H a m l e n a n d K o s k i , 1956).
WF6.4.5SO3, W F e( N H 3 ) 4 , W F e . ( p y) 3 , a n d W F 6( C H 3 N H 2) 3 h a v e been r e p o r t e d (Clark a n d E m e l é u s , 1957). T h e reactions of t u n g s t e n ( V I ) chloride w i t h a m m o n i a a n d amines h a v e been systematically s t u d i e d in r e c e n t years. A m m o n i a below 0° gives simple a d d u c t s , b u t a b o v e t h i s t e m p e r a t u r e ammonolysis occurs of 2, 3, a n d 4 W—CI b o n d s (Fowles a n d Osborne, 1959). T h e reactions w i t h amines are s u m m a r i z e d in T a b l e X X I I . T h e h e x a h a l i d e s are w e a k l y p a r a m a g n e t i c ( K l e m m a n d Steinberg, 1936).
E x t e n s i v e studies on t h e infrared a n d R a m a n s p e c t r a of t h e h e x a
fluorides agree w i t h a s y m m e t r y 0;^. H o w e v e r , one R a m a n line ( I ' L ^ I G ), s t r o n g l y polarized, n e e d s explaining ( T a n n e r a n d D u n c a n , 1951). T h e
f u n d a m e n t a l b a n d a s s i g n m e n t s a r e given in T a b l e X X I I I ( B u r k e et al., 1952). O t h e r w o r k e r s agree, in t h e m a i n , w i t h t h e listed results ( B u r k e a n d S m i t h , 1951; T a n n e r a n d D u n c a n , 1951; G a u n t , 1953; Claassen et al., 1962). I t is t h o u g h t from ^^F n . m . r . studies t h a t below t h e s o l i d -solid t r a n s i t i o n p o i n t (Table X X I , p . 277) for t h e hexafluorides mole
cular r o t a t i o n stops (Cady a n d H a r g r e a v e s , 1961a).
TABLE X X I I I . F u n d a m e n t a l b a n d s i n t h e i n f r a r e d a n d R a m a n s p e c t r a o f M o F e a n d W F g ^ ( c m - ^ )
280 J. Ε . F E R G U S S O N
Metal A F , A F e - A F ,
-Mo 741 623(K) 645(K) 640(NO) 6 2 7 ( Ν θ 2 )
W 712 594(K) 620(K, N O , NO2)
A solution of t u n g s t e n hexachloride in p h o s p h o r y l chloride gives t h e ion WCl?", stable only in excess solvent (Baaz et al., 1961; G u t m a n n , 1960).
(iii) Oxyhalides
T h e oxyfluorides of m o l y b d e n u m a n d t u n g s t e n ( V I ) are AOgFg a n d AOF4; t h e former is doubtful for t u n g s t e n . T h e c o m p o u n d s h a v e n o t b e e n s t u d i e d t o a n y g r e a t e x t e n t since t h e early w o r k of Ruff a n d co
workers (see Gmelin, 1933, 1935).
M o l y b d e n u m dioxydifluoride is o b t a i n e d b y t r e a t i n g t h e correspond
ing chloride w i t h H F , or fluorinating t h e trioxide w i t h selenium (ii) Halide complexes
T h e complex fluoro anions A F 7 - a n d AFg^" h a v e b e e n isolated r e cently. T h e m a i n p r e p a r a t i v e r e q u i r e m e n t is t h e t y p e of solvent, for e x a m p l e , iodine pentafluoride. A F 7 - (Mo a n d W ) is isolated w i t h t h e cations N O , NOg, R b , Cs, NH4, while t h o s e associated w i t h AFg^- are N a , K , R b , Cs. I o d i n e pentafluoride a n d chlorine trifluoride h a v e been used as t h e solvents for reacting t h e hexafluorides w i t h M I or M F (Hargreaves a n d Peacock, 1958a,c; Nikolaev a n d S u k h o v e r k h o v , 1961).
T h e i n t e r a c t i o n of t h e hexafluoride w i t h M F is described as a m e t h o d (Cox et al., 1956; K a t z , 1964), b u t it a p p e a r s t h a t in absolutely d r y con
ditions n o p r o d u c t s are formed (Clark a n d E m e l é u s , 1957; H a r g r e a v e s a n d P e a c o c k , 1958a). I t is possible t h a t t h e hexafluorides used b y Cox et al. (1956) were c o n t a m i n a t e d w i t h b r o m i n e trifluoride, w h i c h m a y h a v e a c t e d as a solvent m e d i u m . T h e nitrosyl p r o d u c t s are formed according t o t h e general r e a c t i o n
N O , F ( g ) + MFe(g) ^ N O ^ F M F e ^ N O + M F ^
Molecular c o m p o u n d
w h e r e a: = 1 or 2 (Geichman et al., 1963).
T h e fluoro complexes are w h i t e in colour a n d readily hydrolysed.
I n f r a r e d studies h a v e allowed t h e M—^F s t r e t c h i n g frequency (vg) t o b e assigned (Table X X I V ) (Peacock a n d S h a r p , 1959; G e i c h m a n et al.,
1963). T h e results for MF7- differ little from MFg- a n d suggest t h a t t h e s t r u c t u r e is a d i s t o r t e d o c t a h e d r o n . Similarly, K2WF8 h a s a cubic u n i t cell suggesting a basic o c t a h e d r a l coordination ( H a r g r e a v e s a n d P e a cock, 1958a).
TABLE X X I V . A — F S t r e t c h i n g m o d e s i n A F e , A F e " a n d
AF7-HALIDE CHEMISTRY OF CHROMIUM, MOLYBDENUM AND TUNGSTEN 281
282 J. Ε . FERGUSSON
HALIDE CHEMISTRY OF CHROMIUM, MOLYBDENUM AND TUNGSTEN 283 M o l y b d e n u m ( V I ) dioxydichloride h a s been described a s w h i t e , yellow, a n d orange, t h e yellow sample a t least seems t o b e a hydrolysis p r o d u c t . M0OCI4 is r e p o r t e d a s a m o n o m e r i n t h e gaseous s t a t e (Glukhov a n d R o d i o n o v a , 1959), as m o s t p r o b a b l y are all t h e o t h e r com
p o u n d s , while a s solids t h e y are likely t o b e polymeric (Shustorovich a n d A t o v m y a n , 1963).
T h e t u n g s t e n oxychloro c o m p o u n d s (especially W0Cr4) form com
plexes w i t h a m m o n i a (Spacu, 1940), amines ( P r a s a d a n d K r i s h n a i a h , 1961a,b), ether, acetonitrile a n d aoc'-dipyridyl ( F u n k a n d M a h a u p t , 1962). I t is a p p a r e n t t h a t solvolysis of t h e W—CI b o n d s is n o t a s easily achieved a s in t h e hexachloride.
Salts of t h e oxyhalides a r e a l m o s t entirely confined t o t h e fiuorides a n d these a r e m a n y a n d varied. T a b l e X X V I I lists t h e anions k n o w n a n d t h e p r e p a r a t i v e details of recent work. E a r l i e r w o r k is reviewed i n Gmelin (1933, 1935), Sidgwick (1950) a n d P e a c o c k (1960).
Clearly, t h e coordination n u m b e r a n d charge a r e t h e factors limiting t h e n u m b e r of anions formed. T h e species AO2F42- a n d AO^F^^' a r e t h e m o s t c o m m o n , while A O F 5 - a n d A 0 4 F ^ - h a v e only r e c e n t l y b e e n p r e p a r e d .
I n a d d i t i o n t o t h e s e c o m p o u n d s even m o r e complex fiuorides h a v e been r e p o r t e d ( S c h m i t z - D u m o n t a n d OpgenhofF, 1954; M a t e i k o a n d B u k h a l o v a , 1955; Nikolaev a n d Opalovskii, 1959b).
T h e complexes i n t h e m a i n a r e stable t o m o d e r a t e h e a t a n d i n a d r y , inert a t m o s p h e r e . I n moist air t h e y u n d e r g o hydrolysis. H o w e v e r ,
^2(^02^4) a p p e a r s r e s i s t a n t t o hydrolysis ( S c h m i t z - D u m o n t a n d H e c k m a n n , 1952; J a n d e r a n d Fiedler, 1961). Very little else is k n o w n a b o u t t h e c o m p o u n d s except for t h e sparse s t r u c t u r a l d a t a listed i n T a b l e X X V I I . T h e ease of formation of t h e a n i o n MOgFg^- a p p e a r s t o increase w i t h cation size ( S c h m i t z - D u m o n t et al., 1952).
I n a d d i t i o n t o t h e a b o v e c o m p o u n d s , p e r o x y fiuoro anions h a v e been k n o w n for m o l y b d e n u m a n d t u n g s t e n for some t i m e , b u t only recently h a v e been s t u d i e d i n detail. T h e a d d i t i o n of h y d r o g e n peroxide t o Κ 2[ Μ Α θ 2 Ε 4 ] Η 2 θ gives K 2[ M o 0 3 F 4 ] H 2 0 a n d K 2[ M o 0 4 F 2 ] H 2 0 . R e p e a t e d recrystallization of t h e former from 6 % H2O2 gives t h e further com
p o u n d KaiMoOgFg]. F o r t u n g s t e n , only K 2[ W 0 3 F 4 ] H 2 0 is formed a s well a s t h e sodium salt. T h e c o m p o u n d s K 2[ A 0 3 F 4 ] (A = Mo, W ) a r e m o n o - p e r o x y a n d K 2[ M o 0 5 F 2 ] is a d i p e r o x y complex. I n f r a r e d a n d fiuorine n.m.r. studies give evidence for t h e d i p e r o x y c o m p o u n d being a p e n t a g o n a l b i p y r a m i d , while t h e m o n o p e r o x y c o m p o u n d s a r e either o c t a h e d r a l or p e n t a g o n a l b i p y r a m i d a l (Grifiith, 1964; E v a n s et al., 1965).
A chloro p e r o x y complex [ M o 0 3 C l 4] 2 - h a s recently been r e p o r t e d w i t h t h e cations NH4, R b , a n d Cs (Wendling et al., 1964).
TABLE XXVH. Oxyfluoride complexes of molybdenum and tungsten(VI) Anion Metal Cations [A04F]«-Mo\ W Na, K, Rb, Cs [AOaFa]^-Mo W K, Rb, Cs, NH4 [AOaF^]^-Mo W K, NH4, Ni, H Κ [AO3F]-W NH^ [AO^F,]^- [AO^FJ^-Mo Mo\ W ) NH4 wide variety [AO2F3]- [AOF,]-w Mo W
NH4 Rb, Cs, NO, NO2 Na, K, Rb, Cs, NO, NO2 Preparation, remarks and references Structural data and references MF—M2AO4 melts Hydrolysis of [MoOgFaJ^- There is no Li compound MF—AO3 melts AO3—MF—aq.HF particularly when MF:A03> 6:1 AO3MF—aq.HF the more soluble products NiMo04 + SF4 Product of hydrolysis of system WO3—NH4F—H2O Seven coordinate? AO3—MF—aq.HF solution especially when MF : AO3 < 6:1 Reported as a monohydrate AFg + moist MF in solvents IF5, SO2, N2O4 W(CO)6 + NaI(l:l)inIF5 WO3-KF + SeF4
1, 2 1-5, 6b,d 4, 5, 6a,b,c, 7 4, 6a,b,c, 10 11 12a,c, 13, 14, 16
isostructural 15 Na, K, (Mo) Na, K, Rb(W)/' Cs, Rb, (Mo) isostructural Κ, Rb and Cs salts of both metals isomorphous 3 K2[Mo02F4] monoclinic 17 Na, Rb, Cs (Mo)^ isostruc- 12a,c Na(W) } turalwith j AFe- 1, Schmitz-Dumont and Opgenhoff (1952); 2, Schmitz-Dumont and Heckmann (1952); 3, Schmitz-Dumont et al. (1952); 4, Schmitz- Dumont and Opgenhoff (1954); 5, Opalovskii et al. (1962); 6, Nikolaev and Opalovskii (1959a,b,c,d); 7, Smith (1959); 8, Opalovskii et al. (1963); 9, Gmelin (1935); 10, Jander and Fiedler (1961); 11, Gmelin (1933); 12, Hargreaves and Peacock (1958a,c); 13, Geichman et al. (1962a); 14, Bartlett and Robinson (1961); 15, Schmitz-Dumont and Weig (1951); 16, Ralston and Musil (I960); 17, Grandjean and Weiss (1963).
284 J. Ε. FERGUSSON
H A L I D E C H E M I S T R Y O F C H B O M I U M , M O L Y B D E N U M A N D T U N G S T E N 285
Recent Developments Note added in proof
T h e following p a p e r s h a v e a p p e a r e d since t h i s article w a s s u b m i t t e d . I n m o s t cases only t h e references are given a n d a n o t e of t h e sections t o w h i c h t h e y refer.
Section 2A
K e n t , R . A. a n d M a r g r a v e , J . L . (1965). J . Am. chem. Soc. 8 7 , 3582.
Section 2B(i, ii)
Cavell, R . G. a n d Clark, H . C. (1965). J. Chem. Soc. àU.
O s m o n d , W . P . (1966). Proc. R. Soc. 8 7 , 767.
R o e s k y , H . , Glemser, 0 . a n d Hellberg, K. H . (1966). Chem. Ber. 99, 459.
T h e electronic s p e c t r a of c h r o m i u m (II) fluoride a n d chloride a n d complex c h r o m i u m ( I I ) fluorides h a v e b e e n s t u d i e d in detail. T h e b a n d s in t h e regions 9050-9600 c m- i , 10,950-11,850 cm-^ a n d 14,000-15,200 c m- i for t h e c o m p o u n d s KCrFg, NaCrFg, Na2CrF4, CrFg a n d CrF2.2H20 h a v e b e e n assigned t o t h e t r a n s i t i o n s ^B^g ^A^g, ^B^g
^B^g a n d ^B^g^^Eg respectively in D^h s y m m e t r y . H i g h e r e n e r g y b a n d s a r e p r o b a b l y q u i n t e t -> t r i p l e t t r a n s i t i o n s . Gaseous c h r o m i u m ( I I ) chloride, w h i c h is largely m o n o m e r i c w i t h a linear s t e r e o c h e m i s t r y , h a s t w o ligand fleld b a n d s a t 5400 a n d 9000 cm-^ assigned t o t h e split s t a t e .
D e K o c k , C. W . a n d G r u e n , D . M. (1966). J. chem. Phys. 44, 4387.
H o l l o w a y , W . W . a n d K e s t i g i a n , M. (1966). Spectrochim. Acta 2 2 , 1381.
Oelkrug, D . (1966). Ber. Bunsen. Phys. Chem. 7 0 , 736.
0 y e , H . A. a n d G r u e n , D . M. (1964). Inorg. Chem. 3, 836.
A r e p o r t of X - r a y p o w d e r diffraction d a t a on t h e complexes KCrFg a n d Na2CrF4 gives t h e C r —F b o n d l e n g t h s : 2 a t 1 -95 Â, 2 a t 2-00 Â a n d 2 a t 2-32 Â for KCrFg a n d 4 a t 1 -96 Â a n d 2 a t 2-45 Â for Na2CrF4. T h e results for t h e former c o m p o u n d disagree w i t h t h o s e of E d w a r d s a n d P e a c o c k (1959).
Oelkrug, D . (1966). Ber. Bunsen. Phys. Chem. 7 0 , 736.
Oxychloro complexes of t h e t w o m e t a l s h a v e b e e n r e p o r t e d b u t n o t s t u d i e d in a n y detail. T h e c o m p o u n d s a r e KiMoOgClglTHgO, K2[Mo02Cl4]2H20, (NH4)2[Mo02Cl4]2H20 ( N e u m a n n a n d Cook, 1957), a n d NaiWOsCl], KiWOgCl] ( P r i g e n t a n d Caillet, 1963). T h e l a t t e r p a i r h a v e been o b t a i n e d from t h e r e a c t i o n of t h e t r i o x i d e a n d alkaH chloride a t 570-630° in a n i t r o g e n a t m o s p h e r e .
286 J. Ε . F E R G U S S O N
Section 2C(i)
Dillon, J . P . a n d Olson, C. E . (1965). J. appl Phys. 3 6 , 1259.
H a n l o n , J . T. a n d Dillon, J . F . (1965). J. appl Phys. 3 6 , 1269.
J e n n i n g s , L . D . a n d H a n s e n , W . N . (1965). Phys. Rev. 139, 1694.
J u n g , W . (1965). J. appl. Phys. 3 6 , 2422.
N a r a t h , A. (1965). Phys. Rev. 140, 854.
S h c h u k a r e v , S. Α., Vasilkova, I . V., Efimov, A. I . a n d P i t r i m o v , B . Z.
(1966). Zh. neorg. Khim. 1 1 , 452.
Y a m a d a , M. (1963). J. phys. Soc. Japan 18, 1696.
Section 2C(ii)
Elwell, D . (1964). Proc. phys. Soc. 84, 409.
F e n s k e , R . F . , Caulton, K . G., R a d t k e , D . D . a n d Sweeney, C. C. (1966).
Inorg. Chem. 5, 960.
G a r r e t t , B . B . , D e A r m o n d , K . a n d G u t o w s k y , A. S. (1966). J. chem.
Phys. 4 4 , 3393.
Section 2D(i)
N o v i k o v , G. I . a n d Galitskii, N . V. (1965). Russ. J. inorg. Chem. 10, 313.
Section 2D(ii)
B r o w n , D . H . , D i x o n , K . R., K e m m i t t , R . D . W . a n d S h a r p , D . W . A.
(1965). J. chem. Soc. 1559.
Y o n e y a m a , S. a n d H i r a k a w a , K . (1966). J. phys. Soc. Japan 2 1 , 183.
Section 2E(iii)
G a r i f y a n o v , N . S. (1964). Dokl Akad. NaukSSSR 155, 385.
G a r i f ' y a n o v , N . S., F e d o t o v , V. N . a n d K u c h e r y a v e n k o , N . S. (1964).
Izv. Akad. Nauk SSSR. Ser. Khim. 743.
Section 2F{i)
Hellberg, K . H . , Mueller, A. a n d Glemser, O. (1966). Z. Naturf. 21b, 118.
Section 2F(ii)
B a r t l e t t , N . , B e a t o n , S. P . a n d J h a , N . K . (1966). Chem. Commun. 168.
K a t z , S. (1966). Inorg. Chem. 5, 666.
Section 2F(iii)
D r a g o , R . S. a n d W h i t t e n , K . W . (1966). Inorg. Chem. 5, 677.
Section 3B(i)
M u r r a y , G. A . (1965). U . S . A t o m i c E n e r g y Commission p u b l i c a t i o n I S - T - 5 .
Schafer, H . a n d S i e p m a n n , R . (1966). J. less-common Metals 1 1 , 76.
A n interesting a p p r o a c h t o t h e b o n d i n g in t h e m o l y b d e n u m (II) cluster MogClg is t o consider t h a t each bridging halogen d o n a t e s t w o
HALIDE CHEMISTRY OF CHROMIUM, MOLYBDENUM AND TUNGSTEN 287
electrons t o a t h r e e - c e n t r e b o n d formed b y each g r o u p of t h r e e m o l y b d e n u m a t o m s a t t h e corners of t h e t r i a n g u l a r faces of t h e m o l y b d e n u m (Mog) o c t a h e d r o n (Fig.2, p . 250).
K e t t l e , S. F . A. (1965). Theoret. chim. Acta 3, 211.
Section 3C(ii)
Aleonard, S. (1965). C.r. hebd. Séanc. Acad. Sci., Paris 2 6 0 , 1977.
v a n D a l e n , P . Α., Gijsman, H . M., L o v e , N . a n d F o r s t a t , H . (1964).
Proc. 9th Int. Conf. Low Temperature Physics, Columbus, Ohio, p . 888.
Section 3D(ii)
Efimov, A. I., Vasilkova, I . V., S m i r n o v a , E . K., Zaitseva, N . D . , S h e m y a k i n a , T. S. a n d Perfilova, I . L. (1964). Khim. Redkikh Elem. Leningr. Gos. Univ. 38.
Section 3E(i)
A n u m b e r of investigations h a v e b e e n carried o u t on t h e p e n t a h a l i d e s of m o l y b d e n u m a n d t u n g s t e n .
B a d e r , R . F . W . a n d H u a n g , K . P . (1965). J. chem. Phys. 4 3 , 3760.
Brisdon, B , J . a n d Fowles, G. W . (1964). J. less-common Metals 7, 102.
S h c h u k a r e v , S. A. a n d K o k o v i n , G. A. (1964). Russ. J. Inorg. Chem.
9, 715.
A c c u r a t e m e a s u r e m e n t s of t h e m a g n e t i c m o m e n t s of t u n g s t e n p e n t a c h l o r i d e a n d p e n t a b r o m i d e h a v e b e e n d e t e r m i n e d . T h e values are
1-01-1-05 Β a n d 1-01-1-03 Β respectively, after correcting for a T I P c o m p o n e n t . T h e m a g n e t i c d a t a , c o n d u c t i v i t y a n d p o t e n t i o m e t r i c analysis of ionic halogens h a s b e e n used as evidence for t h e halides h a v i n g a t r i m e r i c s t r u c t u r e [WgXiaJ^^SX-. H o w e v e r , t h e halides r e a c t w i t h t h e solvent m e t h y l c y a n i d e which m a y i n v a l i d a t e d e d u c t i o n s of a s t r u c t u r a l n a t u r e from t h e c o n d u c t i v i t y a n d p o t e n t i o m e t r i c analysis d a t a .
Colton, R . a n d T o m k i n s , I . B . (1966). Aust. J. Chem. 19, 759.
Section 3E{iii)
S a b a t i n i , A . a n d B e r t i n i , I . (1966). Inorg. Chem. 5, 204.
W e n t w o r t h , R . A. D . a n d P i p e r , T . S. (1964). J. chem. Phys. 4 1 , 3884.
I t h a s b e e n suggested t h a t t h e p r e d o m i n a n t m o l y b d e n u m ( V ) species in h y d r o b r o m i c acid is t h e d i m e r (MoOBrj^ )2.
Allen, J . F . a n d N e u m a n n , H . M. (1964). Inorg. Chem. 3, 1612.
T h e oxychloride WOCI3 h a s r e c e n t l y b e e n p r e p a r e d as a n olive-green residue from t h e reaction of WOCI4 a n d a l u m i n i u m p o w d e r in a sealed t u b e a t 100-140°. T h e c o m p o u n d is slightly p a r a m a g n e t i c a n d h a s a single s t r o n g infrared b a n d a t 796 cm-^. I t is suggested t h a t t h e
288 J. Ε . F E R G U S S O N
c o m p o u n d is polymeric w i t h t h e dimeric entities (WOGl3)2 linked t o g e t h e r in chains t h r o u g h oxy-bridges. I t a p p e a r s t o be s t r u c t u r a l l y analogous t o NbOClg.
Fowles, G. W . A. a n d F r o s t , J . L . (1966). Chem, Commun. 252.
Section 3F(i)
T h e hexahalides h a v e been investigated b y a n u m b e r of workers.
Hellberg, K . H . , Mueller, A. a n d Glemser, 0 . (1966). Z. Naturf. 21b, 118.
Hiraishi, J . , N a k a g a w a , I . a n d S h i m a n o u c h i , T. (1964). Spectrochim.
Acta 2 0 , 819.
N o v i k o v , G. I . a n d Galitskn, N . V. (1965). Russ. J. inorg. Chem. 10, 313.
Osborne, D . W . , Schreiner, F . , M a l m , J . G., Selig, H . a n d R o c h e s t e r , L.
(1966). J. chem. Phys. 4 4 , 2802.
T h e r e a c t i v i t y of t h e fluorides increases in t h e order, W F e < MoF^
< CrFg. B y i n t e r p o l a t i o n , it is v e r y likely t h a t CrFg is t h e m o s t reactive fluoride.
O'Donnell, T . A. a n d S t e w a r t , D . F . (1966). Inorg. Chem. 5, 1434.
Section 3 F (iii)
B a r d a w i l , A. B . , Collier, F . N . a n d Tyree, S. Y. (1965). J. less-common Metals 9, 20.
E d w a r d s , D . A. a n d Woolf, A. A. (1966). J. chem. Soc. (A) 91.
L a r s o n , M. L . a n d Moore, F . W . (1966). Inorg. Chem. 5, 801.
Schroeder, F . (1965). Naturwissenschaften 5 2 , 389.
S h c h u k a r e v , S. A. a n d K o k o v i n , G. A. (1964). Russ. J. inorg. Chem.
9 , 849.
T u c k , D . G. a n d Faithful, B . D . (1965). J. chem. Soc. 5753.
Zelikman, A. N . , D m i t r i e v , Y u . M . a n d K h a z a n , A. Z. (1965). Izv.
Akad. Nauk SSSR, Neorg. Mater. 1 , 1582.
T h e dioxydi-iodo c o m p o u n d WO2I2 h a s been r e p o r t e d recently from t h e reaction of t u n g s t e n m e t a l , t u n g s t e n trioxide a n d excess iodine in a sealed t u b e w i t h a t e m p e r a t u r e g r a d i e n t of 800-300°. T h e c o m p o u n d decomposes w h e n h e a t e d in vacuo b u t sublimes u n c h a n g e d in a n a t m o sphere of iodine. I t s existence is p r o b a b l y related t o t h e stability of t h e t u n g s t e n ( I V ) o x i d a t i o n s t a t e .
Tillack, J . a n d Eckerlin, P . (1966). Angew. Chem. {Int. Edn) 5, 421.
T h e s t r u c t u r e s of b o t h WOCI4 a n d W 0 B r 4 h a v e b e e n d e t e r m i n e d a n d consist of a l m o s t s q u a r e p l a n a r u n i t s WX4, linked in chains t h r o u g h t h e o x y g e n a t o m s . B o n d l e n g t h s a r e : W—CI = 2·28 Â, W — B r = 2-45 Â a n d W — 0 = 2-2 a n d 1-8Â, indicating t h a t t h e stereochemistry a r o u n d t h e t u n g s t e n is a d i s t o r t e d o c t a h e d r o n .
H a r t u n g , H . (1964). Z. Chem. 4, 232.
H e s s , H . a n d H a r t u n g , H . (1966). Z. anorg. allg. Chem. 344 157.
H A L I D E C H E M I S T R Y O F C H R O M I U M , M O L Y B D E N U M A N D T U N G S T E N 289
290 J. Ε. FERGUSSON
H A L I D E C H E M I S T R Y O F C H R O M I U M , M O L Y B D E N U M A N D T U N G S T E N 291
292 J . Ε . F E R G U S S O N
H A L I D E C H E M I S T R Y O F C H R O M I U M , M O L Y B D E N U M A N D T U N G S T E N 293
294 J. Ε. FERGUSSON
H A L I D E C H E M I S T R Y O F C H R O M I U M , M O L Y B D E N U M A N D T U N G S T E N 295
296 J. Ε. FERGUSSON
H A L I D E C H E M I S T R Y O F C H R O M I U M , M O L Y B D E N U M A N D T U N G S T E N 297
298 J. Ε. FERGUSSON
HALIDE CHEMISTRY OF CHROMIUM, MOLYBDENUM AND TUNGSTEN 299
300 J . Ε . F E R G U S S O N
H A L I D E C H E M I S T R Y O F C H R O M I U M , M O L Y B D E N U M A N D T U N G S T E N 301
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