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Complexes Protactinium to Curium
ROBERT A. PENNEMAN, THOMAS Κ. KEENAN, and LARNED B. ASPREY University of California, Los Alamos Scientific Laboratory, Los Alamos, Ν. M. X-ray data are given for tetragonal LiF · XF and for rhombohedral 7NaF · 6XF, X = Th, Pa, U, Np, Pu, Am, and Cm. Hydrogen reduction of alkali fluoride-Pa(V) fluoride complexes yields LiF · PaF and 7MF · 6PaF (where M = Νa, Κ, Rb). When 3NaF · PaF is treated with H at 450°C., its absorption spectrum shows Pa(IV) to be present but its x-ray structure is not changed. Pentavalent compounds in clude MF · PaF , MF · UF (M = Li through Cs), as well as CsF · NpF , CsF · PuF , 2RbF · NpF , 2RbF · PuF , and 3RbF · PaF . Fluorination of UF in liquid anhydrous HF yields UF . When alkali fluoride and UF are present in liquid HF, fluorination forms blue, soluble UF -. Fluorine oxidation of NpF in a melt of CsF · 2HF yields magenta colored NpF -. 4
4
4
4
5
5
2
5
5
5
5
5
5
4
5
4
6
4
6
T n this p a p e r emphasis is g i v e n to recent results o b t a i n e d at t h e L o s A
A l a m o s Scientific L a b o r a t o r y rather t h a n to a c o m p l e t e survey.
Ref
erences to t h e c u r r e n t l i t e r a t u r e w i l l g i v e some i d e a of t h e scope of s u c h work.
Tetravalent Actinide Fluoride Complexes Complexes of
Protactinium ( I V ) .
PREPARATION A N DX - R A Y
PROPER
T I E S . A n u m b e r of c o m p l e x fluorides c o n t a i n i n g other tetravalent actinides are k n o w n (1, 8, 9, 13-15,
20, 22, 24, 25, 26, 27, 29),
but few
248 Fields and Moeller; Lanthanide/Actinide Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1967.
fluoride
18.
Actinide
PENNEMAN ET AL.
compounds
Fluoride
249
Complexes
of P a ( I V ) h a v e b e e n described—e.g., the p r e l i m i n a r y c o m
munications on 7 R b F · 6 P a F of t h e c o m p l e x
fluorides
(3)
4
and 4 N H F 4
are w r i t t e n M F · X F
4
· PaF
(4).
4
or M F · X F
(Formulas 5
for ease of
d i s p l a y i n g the v a l e n c e of the a c t i n i d e . ) O u r p r e v i o u s w o r k o n 4 N H and 4 N H F · A m F 4
( I , 8, 22)
4
N a t i o n a l L a b o r a t o r y (9, 13, 14, 15, 24, 25, 26, 27) (29)
on compounds
4
·UF
4
p l u s the extensive w o r k at the O a k R i d g e
i n the a l k a l i
and b y Zachariasen
fluoride-uranium
p r o v i d e d x - r a y d a t a for the U ( I V )
fluoride
tetrafluoride systems
complexes.
I n most
cases,
the x - r a y properties of the P a ( I V ) c o m p o u n d s are s i m i l a r to those of t h e i r U(IV)
analogs.
Table I. Ratio MF:PaF,
A l k a l i Fluoride Complexes of Tetravalent Protactinium
M
t
Lattice Parameter,
Structure
Li Tetragonal Na Rhombohedral Κ Rhombohedral Rb Rhombohedral Cs (Unknown) All unknown Na Prob. tetragonal
1:1 7:6
a α α α
a
Q
b
6
5
2:1 3:1
ο ο ο
= = = =
A
14.96, c = 6.58 9.16, =107°54' 9.44,α=107°09' 9.64,α=107°0' Q
α
0
4:1
Κ
Prob. fee
Rb
Prob. fee
NH
4
Existence inferred from absorption spec trum, amount P a ( I V ) and of P a ( V ) unknown/ Existence inferred from absorption spec trum, amount P a ( I V ) and of P a ( V ) unknown/ Existence inferred from absorption spec trum, amount P a ( I V ) and of P a ( V ) unknown/ Isostructural w i t h ( N H ) X F ( X = U , N p , P u , and A m )
Monoclinic
4
4
8
° Isostructural with L i F · U F (13, 14). Isostructural with 7NaF · 6 U F (13, 15). Hydrogen reduction of 2 K F · P a F powder resulted in the formation of 7 K F · 6 P a F as the major solid phase, and not 2 K F · P a F . T h e x-ray structures of the 1:1 alkali fluoride : PaFs fluoride complexes are quite distinct from those of the 1:1 and 7:6 alkali fluoride:PaF complexes. At the 3:1 stoichiometry, the 3 K F · U F , 3 K F · U F , and 3 K F · U F compounds are all facecentered cubic and of nearly identical cell size (28). Absorption spectrum rather than x-ray was the criterion used to detect hydrogen reduction of 3 K F · P a F to 3 K F · P a F , and of 3NaF · P a F to 3NaF · P a F . 4
b
4
c
5
4
4
d
4
3
4
5
5
4
5
Complex fluorides
fluorides
4
c o n t a i n i n g tetravalent p r o t a c t i n i u m a n d the a l k a l i
( L i , N a , K , R b , a n d N H ) w e r e p r e p a r e d f r o m M F -f4
starting mixtures a n d b y reducing M F - P a F , compounds r
PaF
4
at 4 0 0 ° - 5 0 0 ° C .
u s i n g p u r e h y d r o g e n , o b t a i n e d f r o m U H . T h e x - r a y results o n 3
p o u n d s o b t a i n e d b y these m e t h o d s are p r e s e n t e d i n T a b l e I.
Fields and Moeller; Lanthanide/Actinide Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1967.
com
250
LANTHANIDE/ACTINIDE CHEMISTRY
A B S O R P T I O N
S P E C T R U M
should have a 5/
O F
7RbF * 6PaF .
Tetravalent protactinium
4
e l e c t r o n a n d s h o w discrete o p t i c a l a b s o r p t i o n . T h i s is
1
d e m o n s t r a t e d i n T a b l e I I w h i c h shows the a b s o r p t i o n s p e c t r u m c h a r a c teristic of tetravalent p r o t a c t i n i u m . T h e s p e c t r u m w a s o b t a i n e d f r o m a m u l l i n a Fluorocarbon oil, held between
CaF
flats.
2
A C a r y 14 M R
spectrophotometer was used. Table II.
Absorption Spectrum of Tetravalent Protactinium Fluoride Compound
Peak Maxima, A
7RbF · 6PaF
2580 2920 3500 12600 14700 16000 17400 18270 18510
4
M W M S W , Br V W , Br VW VS, Narrow" W
F o r 7 R b F · 6 P a F , 3 N a F · P a F , a n d P a F , an intense infrared absorption b a n d is observed at — 6 4 8 5 c m . " , g i v i n g a value for fa of P a ( I V ) = 1567 c m . " .
a
4
4
4
1
1
Preparation and Lattice Constants of the L i F · X F and 7 N a F · 6 X F 4
(X =
Th —
fluorides
Cm)
(18)
Series.
a n d 7:6
been completed
4
T h e t w o series of 1:1 l i t h i u m - a c t i n i d e ( I V )
sodium-actinide(IV)
fluorides
have
(18)
for a l l a c t i n i d e s , t h o r i u m t h r o u g h c u r i u m (i.e.,
a v a i l a b l e a c t i n i d e s w h i c h e x h i b i t a tetravalent s t a t e ) .
now those
Berkelium would
u n d o u b t e d l y f o r m s i m i l a r c o m p o u n d s , b u t sufficient q u a n t i t i e s w e r e not yet a v a i l a b l e . A l t h o u g h the c o m p o u n d s L i F · T h F L i F · PaF
(13), 6UF
4
(7), 7 N a F · 6PaF
4
(7), L i F · U F
4
4
(13), 7 N a F · 6 T h F (13,14),
4
and 7 N a F ·
( 13 ) h a d b e e n k n o w n p r e v i o u s l y , d a t a for the l i t h i u m a n d s o d i u m
4
double
fluorides
lacking.
of n e p t u n i u m , p l u t o n i u m , a m e r i c i u m , a n d c u r i u m w e r e
These compounds
of either 1:1
L i : X or 7:6
have now been prepared.
Starting mixtures
N a : X were prepared b y evaporation
from
aqueous H C 1 s o l u t i o n . H y d r o g e n r e d u c t i o n of the n e p t u n i u m at 3 5 0 ° C . i n the presence of H F f o r m e d L i F · N p F T r e a t m e n t of
4
and 7NaF · 6 N p F . 4
the s t a r t i n g m i x t u r e s of
p l u t o n i u m , a m e r i c i u m , or
c u r i u m w i t h e l e m e n t a l fluorine at 3 5 0 ° C . for — 16 h o u r s w a s necessary to f o r m g o o d x-ray samples of L i F * X F Cm).
4
or 7 N a F · 6 X F
4
c o n d i t i o n s . W h e n h e a v i e r alkalis are present ( R b or C s ) , such mixtures yields P u ( V )
Pu, Am,
fluorination
of
fluorides.
R e c e n t single c r y s t a l studies o n L i F · U F (15)
(X =
N o o x i d a t i o n to p e n t a v a l e n t p l u t o n i u m w a s o b s e r v e d u n d e r these
4
(14)
and 7 N a F · 6 Z r F
4
e s t a b l i s h e d the space g r o u p assignments a n d s t o i c h i o m e t r y so t h a t
powder diffraction data on the new actinide compounds
could be
Fields and Moeller; Lanthanide/Actinide Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1967.
more
18.
PENNEMAN
ET
Actinide
AL.
Fluoride
r e a d i l y i n t e r p r e t e d . T h e 1:1 L i F * X F
4
251
Complexes
c o m p o u n d s are t e t r a g o n a l , space
g r o u p I 4 i / , w i t h 16 molecules per u n i t c e l l . T h e 7 N a F · 6 X F a
are r h o m
4
b o h e d r a l , space g r o u p R 3 , w i t h three m o l e c u l e s p e r h e x a g o n a l u n i t c e l l . I n b o t h series, a steady decrease i n m o l e c u l a r v o l u m e is n o t e d
from
t h o r i u m to c u r i u m w h i c h is e v i d e n c e for the a c t i n i d e c o n t r a c t i o n i n the t e t r a v a l e n t state. compounds.
F i g u r e 1 shows this c o n t r a c t i o n for the t w o types of
C e l l constants for these t w o series are g i v e n i n T a b l e I I I .
Rb" Κ
7:6
AF:MF
4
Na
LÎF:MF
Pa
Th
Np __L_
U
Pu
Am
4
Cm
ACTINIDE (IE)
Figure 1.
Molar volumes of rhombohedral Na M F and tetragonal LiMF on the basis of I M atom/molecule 7
6
31
5
Pentavalent Actinide Fluoride Complexes Protactinium(V).
A
new
series of
pentavalent protactinium and alkali
pounds K F · P a F , R b F · P a F , N H F 5
5
complex
fluorides 4
fluorides
containing
w a s s y n t h e s i z e d ; the c o m -
· P a F , and C s F · P a F 5
5
were
s h o w n to b e i s o s t r u c t u r a l ( 2 , 6 ). O t h e r complexes w i t h the r a t i o of one a l k a l i to one p r o t a c t i n i u m w e r e also p r e p a r e d b u t these LiF · PaF
5
a n d N a F · P a F , w e r e not i s o s t r u c t u r a l w i t h the p r e c e d i n g 5
g r o u p n o r w i t h e a c h other ( 6 ) . (M =
compounds,
C o m p l e x e s of the 2:1 t y p e , 2 M F * P a F
5
K , R b , C s b u t n o t L i or N a ) f o r m r e a d i l y . T h e 3:1 t y p e ( 3 M F ·
P a F ) w e r e also p r e p a r e d , a n d 3 R b F · P a F 5
9.6 A ( 6 ) .
5
w a s i n d e x e d as fee,
T h e s e latter t w o classes of h i g h e r complexes
a
0
=
were studied
to a lesser extent at L o s A l a m o s since it was f o u n d that the E n g l i s h g r o u p at H a r w e l l was i n v e s t i g a t i n g t h e m (10, I I , 1 2 ) . findings
O n e of t h e i r i n t e r e s t i n g
w a s the c o o r d i n a t i o n of n i n e for P a ( V ) i n 2 K F · P a F
t h a n seven as occurs i n the t a n t a l u m a n a l o g .
Fields and Moeller; Lanthanide/Actinide Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1967.
5
rather
252
LANTHANIDE/ACTINIDE CHEMISTRY
Table III.
L i X F ; T e t r a g o n a l , Spac e G r o u p I 4]L / a j Ζ —: 16 r >
Compound LiThF LiPaF LiUF LiNpF LiPuF LiAmF LiCmF
a , A. 0
15.10 14.97 14.8592 14.80 14.67 14.63 14.57
5
5
5
5
5
5
5
Na X F ; 7
Na Na Na Na Na Na Na
6
7 7 7 7 7 7 7
± ± ± ± ± ±
0
6.60 6.576 6.5433 6.516 6.479 6.449 6.437
0.02 0.0096 0.02 0.02 0.02 0.02
Th F Pa F U F Np F Pu F Am F Cm F 6
14.96 14.81 14.72 14.64 14.55 14.48 14.41
3 1
6
3 1
6
3 1
6
3 1
6
3 1
6
3 1
c
3 1
9.912 9.850 9.84 9.785 9.741 9.665 9.661
± 0.02 ± ± ± ±
T h e 1:1 complexes
0.02 0.02 0.02 0.02 between
± ± ± ± ± ±
3
± 0.003 ± ± ± ±
13 7 15 18 18,19 18 18
94.1 92.0 90.3 89.2 87.1 86.3 85.4
0.003 0.0009 0.005 0.005 0.005 0.005
Space Group R3, Ζ =
Hexagonal (Rhombohedral),
sl
Mol. Vol., Reference A.
, A.
0.003 0.003 0.003 0.003
the h e a v i e r a l k a l i
3
640.4 623.7 615.5 605.4 595.3 585.0 579.1
13 7 13 18 18 18 18
fluorides
and pro
t a c t i n i u m p e n t a f l u o r i d e are e s p e c i a l l y i n t e r e s t i n g since t h e y are n o t l i k e t h e i r t a n t a l u m analogs b u t m o r e closely r e s e m b l e those of p e n t a v a l e n t u r a n i u m . W e find t h e m to b e o r t h o r h o m b i c (see
Table I V ) .
Systematic
absences of reflections i n d i c a t e the space g r o u p to b e A b m 2 or A b m m (Cmma).
Reflections of the t y p e h k 1 for w h i c h k a n d 1 are
odd
are e x t r e m e l y w e a k , w h i l e those w i t h k a n d 1 even are g e n e r a l l y q u i t e strong.
T h e i n t e n s i t y d i s t r i b u t i o n of the strong reflections suggest that
at least the a c t i n i d e atoms are i n s u c h s p e c i a l positions as to
produce
a p s e u d o - c e l l of one q u a r t e r the v o l u m e of the t r u e c e l l . U r a n i u m ( V ) . I n the case of u r a n i u m , gaseous fluorine w i l l n o r m a l l y take U F o n past U F to U F . I n contrast, w e find that fluorine o x i d a t i o n 4
of U F
4
5
6
i n l i q u i d a n h y d r o u s H F p r o c e e d s r e a d i l y to U F
5
a n d t h e n goes
o n l y s l o w l y to U F . If a l k a l i fluoride is also present, the m e t h o d is espe 6
c i a l l y u s e f u l i n the p r e p a r a t i o n of M F · U F c o m p o u n d s free f r o m traces 5
of U ( I V ) or U ( V I ) . T h e t e c h n i q u e is g i v e n b e l o w : ( 1 ) W e p r e p a r e d U F b y s t i r r i n g a suspension of h i g h surface area U F i n l i q u i d a n h y d r o u s H F at 2 5 ° C . u n d e r 10 p.s.i.g. of F . T h e o x i d a t i o n c a n be r e a d i l y h a l t e d at / 2 - U F w h i c h is also i n s o l u b l e i n l i q u i d H F . 5
4
2
5
( 2 ) A s t i r r e d s l u r r y of C s F a n d U F ( 1 : 1 m o l e r a t i o ) i n l i q u i d H F w a s t r e a t e d w i t h F at 10 p.s.i.g., r e s u l t i n g i n s m o o t h o x i d a t i o n of U ( I V ) to U ( V ) , g i v i n g a clear b l u e s o l u t i o n of C s F · U F . O n e v a p o r a t i o n of H F , b l u e crystals of p u r e C s F · U F w e r e d e p o s i t e d . W i t h R b F , l i g h t y e l l o w R b F · U F crystals w e r e d e p o s i t e d f r o m the b l u e s o l u t i o n of R b F · U F i n l i q u i d H F . I n these latter reactions, U F n e e d not b e of h i g h surface area since the M F · U F r e a c t i o n p r o d u c t s are soluble. 4
2
5
5
5
5
4
5
Fields and Moeller; Lanthanide/Actinide Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1967.
18.
PENNEMAN
ET AL.
Neptunium ( V )
Actinide
Fluoride
A l t h o u g h U F , U F , and U F
and Plutonium ( V ) .
are w e l l k n o w n c o m p o u n d s ,
253
Complexes 4
e v i d e n c e for N p F
5
and P u F
5
6
is l a c k i n g .
5
U s i n g the m e t h o d w h i c h p r o v e d successful i n p r e p a r i n g U F , w e f o u n d 5
t h a t at 2 5 ° C , N p F to N p F
5
4
(0.17 g r a m s ) as a s l u r r y i n H F w a s n o t o x i d i z e d
b y 10 p.s.i.g. of F . H o w e v e r , w h e n 10 grams of C s F w e r e 2
a d d e d a n d H F p u m p e d off, T h e green N p F
fluorine
t h e n c a u s e d o x i d a t i o n to N p ( V ) .
d i s s o l v e d i n the r e s i d u a l w a r m ( 5 0 ° - 7 0 ° C . ) C s F · 2 H F
4
m i x t u r e a n d was o x i d i z e d b y F complex; C s F - N p F this s o l u t i o n ( 5 ) .
5
2
to a s o l u b l e , m a g e n t a N p ( V ) 5
W h e n l i q u i d H F w a s r e c o n d e n s e d o n this m a t e r i a l ,
d i s p r o p o r t i o n a t i o n took p l a c e , as d e d u c e d green N p F
4
fluoride
(isostructural w i t h C s F · U F ) was deposited from f r o m the o b s e r v a t i o n t h a t
r e m a i n e d b e h i n d a n d orange, v o l a t i l e N p F
the c o n n e c t i n g t r a p . C s F · N p F
5
6
condensed i n
is best p r e p a r e d b y the d r y t e c h n i q u e s
l i s t e d b e l o w for p l u t o n i u m ; d a t a for this c o m p o u n d are g i v e n i n T a b l e I V .
Table IV. Some A l k a l i Fluoride : Protactinium ( V ), U r a n i u m ( V ), N e p t u n i u m ( V ) , P l u t o n i u m ( V ) Fluoride Complexes* (1:1) Isostructural Orthorhombic Compounds
a , A.
b , A.
c , A.
5.64 5.61 5.84 5.83 5.86 5.82 6.14
11.54 11.46 11.90 11.89 11.97 11.89 12.56
7.98 7.96 8.03 8.03 8.04 8.03 8.06
0
0
K F · PaF KF · UF N H F · PaF NH F ·U F RbF · PaF RbF · U F CsF · PaF 5
5
4 4
5
5
5
5
5
0
(Id) Isostructural Rhombohedral Compounds CsF · U F CsF · N p F CsF · P u F
8.39 8.386 8.370
8.04 8.017 8.006
5
5
5
(2:1) Isostructural Monoclinic Compounds 2RbF · N p F 2RbF · P u F
5
5
A complete structure determination of R b P a F Keller (16).
a
13.42 13.41
6.26 6.27 6
6
8.90 (β 8.84 (β
= =
is b e i n g made b y B u r n s , L e v y , a n d
Fields and Moeller; Lanthanide/Actinide Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1967.
254
LANTHANIDE/ACTINIDE
The compounds 2 R b F · P u F
5
and C s F · P u F
5
CHEMISTRY
w e r e t h e first fluoride
c o m p l e x e s to b e c h a r a c t e r i z e d i n w h i c h a t r a n s u r a n i u m e l e m e n t i n t h e p e n t a v a l e n t state occurs w i t h o u t t h e " y l " t y p e of o x y g e n b o n d i n g ( 2 3 ) . F l u o r i n e gas w a s u s e d to o x i d i z e a n h y d r o u s s o l i d m i x t u r e s of r u b i d i u m fluoride
or c e s i u m
fluoride-plutonium(IV)
fluorides
i n 2 : 1 a n d 1:1 m o l e
r a t i o . T h e m i x t u r e s w e r e c o n t a i n e d i n s a p p h i r e boats a n d w e r e e x p o s e d to 6 p.s.i.g. F gas at 3 5 0 ° - 4 0 0 ° C . f o r times v a r y i n g f r o m 4 to 16 hours. 2
The compound 2 R b F c
0
=
8.84, β =
2RbF · NpF UF
5
5
· PuF
5
is m o n o c l i n i c , a
0
=
6.27, b
9 0 ° ; i t is i s o s t r u c t u r a l w i t h 2 K F · T a F
(5). C s F · P u F
5
0
5
—
13.42,
(17) a n d
is r h o m b o h e d r a l , i s o s t r u c t u r a l w i t h C s F ·
( 2 1 ) . D a t a o n these 1:1 c o m p l e x e s are l i s t e d i n T a b l e I V .
Literature Cited (1) Asprey, L. B., Penneman, R. Α., Inorg. Chem. 1, 134 (1962). (2) Asprey, L. B., Penneman, R. Α., Science 145, 924 (1964). (3) Asprey, L. B., Kruse, F. H., Penneman, R. Α., J. Am. Chem. Soc. 87, 3518 (1965). (4) Asprey, L. B., Penneman, R. Α., Centre Natl. Rech. Sci. (Paris) Colloq. Intern. Phys. Chem. 154, 109 (1966). (5) Asprey, L. B., Keenan, T. K., Penneman, R. Α., Sturgeon, G. D., Inorg. Nucl. Chem. Letters 2, 19 (1966). (6) Asprey, L. B., Kruse, F. H., Rosenzweig, Α., Penneman, R. Α., Inorg. Chem. 5, 659 (1966). (7) Asprey, L. B., Kruse, F. H., Penneman, R. Α., Inorg. Chem. 6, 544 (1967). (8) Benz, R., Douglass, R. M., Kruse, F. H., Penneman, R. Α., Inorg. Chem. 2, 799 (1963). (9) Barton, C. J., et al., U. S. At. Energy Comm. Oak Ridge Natl. Lab. Rept. ORNL-2548 (Nov. 2, 1959). (10) Brown, D., Smith, A. J., Chem. Commun. 554 (1965). (11) Brown, D., Easey, J. F., Nature 205, 589 (1965). (12) Brown, D., Easey, J. F., J. Chem. Soc. 1966, 254. (13) Brunton, G. D., Insley, H., McVay, T. N., Thoma, R. E., U. S. At. Energy Comm. Oak Ridge Natl. Lab. Rept. ORNL-3761, (Feb. 1965). (14) Brunton, G. D., U. S. At. Energy Comm. Oak Ridge Natl. Lab. Rept. ORNL-3913, 10 (1966); Acta Cryst. 21, 814 (1966). (15) Burns, J. H., Ellison, R. D., Levy, Η. Α., U. S. At. Energy Comm. Oak Ridge Natl. Lab. Rept. ORNL-3913, 17 (1966); Acta Cryst. (to be pub lished). (16) Burns, J. H., Levy, Η. Α., Keller, O. L., Oak Ridge Natl. Lab. (private communication). (17) Hoard, J. L., J. Am. Chem. Soc. 61, 1252 (1939). (18) Keenan, T. K., Inorg. Nucl. Chem. Letters 2, 153, 211 (1966). (19) Keller, C., Schmutz, H., Inorg. Nucl. Chem. Letters 2, 355 (1966). (20) Kruse, F. H., Asprey, L. B., Inorg. Chem. 1, 137 (1962). (21) Penneman, R. Α., Sturgeon, G. D., Asprey, L. B., Inorg. Chem. 3, 126 (1964). (22) Penneman, R. Α., Kruse, F. H., George, R. S., Coleman, J. S., Inorg. Chem. 3, 309 (1964). (23) Penneman, R. Α., Sturgeon, G. D., Asprey, L. B., Kruse, F. H., J. Am. Soc. 87, 5803 (1965).
Fields and Moeller; Lanthanide/Actinide Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1967.
18.
PENNEMAN ET A L .
Actinide Fluoride Complexes
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(24) Thoma, R. E., Barton, C. J., Friedman, H. Α., Grimes, W. R., Insley, H., Moore, R. E., J. Am. Ceram. Soc. 41, 63 (1958). (25) Thoma, R. E., Insley, H., Landau, B. S., Friedman, H. Α., Grimes, W. R., J. Am. Ceram. Soc. 41, 538 (1958). (26) Thoma, R. E., Inorg. Chem. 1, 220 (1962). (27) Thoma, R. E., Insley, H., Herbert, G. M., Friedman, H. Α., Weaver, C. F., J. Am. Ceram. Soc. 46, 37 (1963). (28) Thoma, R. E., Friedman, H. Α., Penneman, R. Α., J. Am. Chem. Soc. 88, 2046 (1966). (29) Zachariasen, W. H., J. Am. Chem. Soc. 70, 2147 (1948). RECEIVED October 18, 1966. This work was sponsored by the U. S. Atomic Energy Commission.
Fields and Moeller; Lanthanide/Actinide Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1967.
