Actinide Chemistry

---

1 Recent Advances in Actinide and Lanthanide Chemistry K. W . BAGNALL Chemistry Division,

The

A.E.R.E.,

chemistry

americium,

of

the

all being

series.

Their

within

are

cal similarities

In the

All

behave

in much

of the of the

and compared

from

+4,

shows

thorium

to

quantities,

is

or higher oxidation both

as an inner horizontal

states, transition

similarities

group and to a lesser degree, some

with

ments.

actinides

in substantial

best considered

chemistry

the actinide

chemistry

lighter available

now well understood. these elements

H a r w e l l , Didcot, Berks., E n g l a n d

the group actinides

the

with

in their

same way

actinides

verti­

4, 5, and 6 d-transition +3

as the

is reviewed

the corresponding

ele­

oxidation

states

lanthanides. within

this

The context

lanthanides.

Τ η r e v i e w i n g the c h e m i s t r y of the a c t i n i d e s as a g r o u p , t h e simplest A

a p p r o a c h is to consider e a c h v a l e n c e state separately. I n t h e t e r v a l e n t

state, a n d s u c h examples of the d i v a l e n t state as are k n o w n , the a c t i n i d e s s h o w s i m i l a r c h e m i c a l b e h a v i o r to the l a n t h a n i d e s . E x p e r i m e n t a l diffi­ culties w i t h the t e r p o s i t i v e a c t i n i d e s u p to p l u t o n i u m are

considerable

because of the r e a d y o x i d a t i o n of this state. S o m e c o r r e l a t i o n exists w i t h the a c t i n i d e s i n studies of the l a n t h a n i d e tetrafluorides a n d plexes.

F o r other c o m p o u n d s

fluoro

com­

of the 4-valent a c t i n i d e s , p r o t a c t i n i u m

shows almost as m a n y s i m i l a r i t i e s as differences

between thorium and

the u r a n i u m - a m e r i c i u m set; thus i n v e s t i g a t i n g the c o m p l e x f o r m i n g p r o p ­ erties of t h e i r h a l i d e s has a t t r a c t e d attention.

I n the 5- a n d 6-valent

states, the elements f r o m u r a n i u m to a m e r i c i u m s h o w a degree of c h e m i c a l s i m i l a r i t y .

Protactinium ( V )

considerable

behaves i n m u c h t h e

same w a y as these elements i n the 5-valent state except f o r w a t e r , w h e r e its h y d r o l y t i c b e h a v i o r is m o r e r e m i n i s c e n t of n i o b i u m a n d t a n t a l u m . T h i s r e v i e w is l a r g e l y r e s t r i c t e d to w o r k w h i c h has b e e n p u b l i s h e d i n t h e 1960's w i t h emphasis o n the c h e m i s t r y of t h e h a l i d e s a n d t h e i r complexes.

T h e s e h a v e b e e n the subject of most of the recent research, 1

2

LANTHANIDE /ACTINIDE

CHEMISTRY

a n d a c o m p l e t e c o m p a r i s o n of a l l the k n o w n c h e m i s t r y of the l a n t h a n i d e s a n d actinides has not b e e n a t t e m p t e d p r e v i o u s l y .

Divalent State Compounds

of

d i v a l e n t s a m a r i u m , e u r o p i u m , a n d y t t e r b i u m are

w e l l - k n o w n . I n recent years, l o w e r h a l i d e s of other l a n t h a n i d e s , s u c h as neodymium

praseodymium

(48),

(45,

49, 90),

a n d t h u l i u m (4)

have

b e e n o b t a i n e d b y r e d u c i n g the t r i h a l i d e w i t h the m e t a l . T h e c o r r e s p o n d ­ i n g r e a c t i o n of t h o r i u m t e t r a i o d i d e w i t h t h o r i u m m e t a l has l e d to the i d e n t i f i c a t i o n of t w o c r y s t a l l i n e forms of T h l

2

(41, 91);

i t is u n l i k e l y t h a t

the T h , or e v e n T h , i o n is present i n T h l , b u t l i k e P r l , w h i c h is 2 +

3 +

2

f o r m u l a t e d as P r ( I ~ ) ( e ~ ) (2), 3+

Th

4 +

(r) (2e~) 2

2

2

the c o m p o u n d is p r o b a b l y of the t y p e

C e r t a i n l y one c r y s t a l f o r m is d i a m a g n e t i c

(41).

(41),

suggesting the latter f o r m u l a t i o n . I n a d d i t i o n , a l l of the l a n t h a n i d e s h a v e n o w b e e n o b t a i n e d i n the d i v a l e n t state i n d i l u t e s o l u t i o n i n a C a F fused

salt electrolysis

(52),

2

m a t r i x b y γ-irradiation

or a l k a l i n e e a r t h m e t a l r e d u c t i o n

(74), (68).

A t t e m p t s to r e d u c e a m e r i c i u m , the a n a l o g of e u r o p i u m , to this l o w e r o x i d a t i o n state h a v e also b e e n successful u n d e r s i m i l a r c o n d i t i o n s the A m

2 +

ion, w h i c h occupies C a

its E S R s p e c t r u m . unsuccessful

2 +

(51);

sites i n the c r y s t a l , w a s i d e n t i f i e d b y

S i m i l a r attempts to o b t a i n u r a n i u m ( I I )

have been

(51).

Tervalent State I n the l a n t h a n i d e s , the b a s i c c h e m i s t r y of p r o m e t h i u m has b e c o m e better k n o w n because of the a v a i l a b i l i t y of r e l a t i v e l y large q u a n t i t i e s of 1 4 7

P m (103),

the o b s e r v e d b e h a v i o r of the element b e i n g m u c h as one

w o u l d expect. Thl

4

I n the a c t i n i d e s , T h l

w i t h t h o r i u m m e t a l (41, 91)

3

has b e e n p r e p a r e d b y r e a c t i o n of

a n d appears to b e a n i o n i c c o m p o u n d ;

if so, i t w i l l p r e s u m a b l y b e p a r a m a g n e t i c .

W i t h the h i g h e r a c t i n i d e s

b e i n g p r o d u c e d i n large q u a n t i t i e s , it is p l e a s i n g to see c r y s t a l l o g r a p h i c d a t a r e p o r t e d for c a l i f o r n i u m c o m p o u n d s , the e m e r a l d green t r i c h l o r i d e b e i n g h e x a g o n a l ( U C 1 ) , a n d the sesquioxide m o n o c l i n i c ( S m 0 ) 3

2

w h i l e , w i t h the i d e n t i f i c a t i o n of a l o n g e r - l i v e d (79 fermium [

2 5 7

F m (60)]

days)

3

isotope

(58) of

it appears as t h o u g h m i c r o c h e m i c a l studies of a l l

the actinides u p to element 100 w i l l b e c o m e p r a c t i c a b l e . Studies of the c o m p l e x c h e m i s t r y of the t e r v a l e n t l a n t h a n i d e s s h o w that c o o r d i n a t i o n n u m b e r s h i g h e r t h a n six are c o m m o n , for e x a m p l e i n the tetrakistropolonates (79),

the complexes

d i m e t h y l a c e t a m i d e ( D M A ) (77)

of the perchlorates w i t h

or o c t a m e t h y l p y r o p h o s p h o r a m i d e

of the i o d i d e s w i t h Ν,Ν-dimethylformamide ( D M F ) w i t h triphenylphosphine (or

arsine)

oxide

(46),

(76),

a n d the

N,N(61),

the nitrates β-diketone

1.

BAGNALL

chelates (28);

Recent

Advances

m a n y of these complexes are d i s c u s s e d later i n this v o l u m e .

A c t i n i d e ( I I I ) analogs d o not seem to h a v e b e e n p r e p a r e d . I n t h e i r h a l o complexes, the l a n t h a n i d e s ( I I I )

a n d actinides

(III)

s h o w a c o n s i d e r a b l e s i m i l a r i t y . T h u s tetrafluorolanthanides ( I I I ) a n d -actinides ( I I )

(65,

72)

(100)

h a v e b e e n r e p o r t e d , a l l of t h e m h a v i n g

hexagonal symmetry, and hexahalolanthanides (III)

a n d some a c t i n i d e

( I I I ) analogs h a v e also b e e n p r e p a r e d ; the t r i p h e n y l p h o s p h o n i u m h e x a chlorolanthanides (III)

have been isolated from nonaqueous

solvents,

a n d t h e i r v i s i b l e spectra h a v e b e e n d i s c u s s e d i n some d e t a i l (62, T h e corresponding americium (III)

89).

salt c a n b e m a d e i n a s i m i l a r m a n -

ner ( 8 7 ) , b u t the aqueous a l k a l i c h l o r i d e / A m C l system is m o r e c o m p l i 3

c a t e d , the species C s A m C l

4

· 4 H 0 and C s N a A m C l 2

2

6

b e i n g isolated from

aqueous s o l u t i o n a n d " C s A m C l " f r o m e t h a n o l i c h y d r o c h l o r i c a c i d s o l u 3

6

tions of the c o m p o n e n t s ( 2 5 ) ; this last m a y , h o w e v e r , b e C s A m C l i . 8

plutonium compound, C s P u C l 3

h y d r o c h l o r i c a c i d (95).

6

3

7

The

· 2 H 0 , has b e e n i s o l a t e d f r o m aqueous 2

M a n y more lanthanide and actinide halo complex

species h a v e b e e n r e p o r t e d for f u s e d salt m e l t s , r a n g i n g i n the case of the c h l o r i d e s f r o m the s i m p l e M C L f i o n to M C 1 " a n d M C l i 2

9

3

3

0

a

" ; some

examples are s h o w n i n T a b l e I. M a n y of t h e m exist o n l y i n f u s e d salts a n d h a v e not b e e n p r e p a r e d b y other means. Table I.

Anionic Chlorocomplexes in Fused Salts

Anion

Metal

MCLf MC1 MCV" MC1 " M C1 5

9

2

2

6

7

M CVM C1 2

3

1 0

Reference

(M)

9 9, 72, 78, 80, 97, 98 9, 59, 69, 72, 78, 80, 97, 98 72 72, 80 9, 59 9, 69

La L a , Ce, Pr, N d , Sm, Pu Se, Y , L a , C e , P r , N d , S m , Y b , P u Pu Sm, P u Se, C e , P r , N d Y, L a , Ce

Tetravalent State I n the 4-valent state of the elements, one of the most r e m a r k a b l e p r e p a r a t i v e reactions r e p o r t e d r e c e n t l y is the i s o l a t i o n of P r F sodium

fluoride

f r o m the c o m p l e x N a P r F 2

presence of fluorine (92).

6

4

by washing

w i t h a n h y d r o u s H F i n the

T h e structures of P r F

4

a n d its fluoro complexes

are analogous to those of the c o r r e s p o n d i n g u r a n i u m c o m p o u n d s a n d e v i d e n c e has b e e n o b t a i n e d for the f o r m a t i o n of P r ( I V ) species i n the r e a c t i o n of P r O n or P r 0 6

A v a r i e t y of

fluoro

complexes

formed

2

w i t h dinitrogen pentoxide

(93).

b y t h e 4-valent elements

from

p r o t a c t i n i u m to c u r i u m h a v e also b e e n r e p o r t e d r e c e n t l y A n u n u s u a l l a y e r s t r u c t u r e has b e e n f o u n d for T h l existence

of

PaCl

4

has n o w

been

(I),

nitrato

confirmed.

4

PaOCl , 2

(82). (104), PaOBr

a n d the 2

(31),

4

LANTHANIDE/ACTINIDE

PaBr

4

PaOI , and P a l

(33),

2

CHEMISTRY

(31 ) a n d some of t h e i r complexes, i n c l u d i n g

4

h e x a c h l o r o - , h e x a b r o m o - , a n d h e x a i o d o p r o t a c t i n a t e s ( I V ) (33) prepared. P a B r

have been

appears to b e i s o s t r u c t u r a l w i t h one f o r m of T h B r

4

4

and

n o t w i t h m o n o c l i n i c U B r . H e x a c h l o r o complexes of a l l the a c t i n i d e s ( I V ) 4

f r o m t h o r i u m to p l u t o n i u m are n o w o n r e c o r d , o n l y ( N E t ) T h C l 4

2

6

being

r e p o r t e d as d i m o r p h i c . A l l the analogous h e x a b r o m o complexes are also k n o w n since the n e p t u n i u m ( I V ) a n d p l u t o n i u m ( I V ) c o m p o u n d s b e e n i s o l a t e d f r o m e t h a n o l i c h y d r o b r o m i c a c i d (88). thorium ( I V ) , and uranium ( I V )

(37),

h e x a i o d o complexes

(16)

have

Protactinium ( I V ) are

m o r e difficult to o b t a i n , i n a c c o r d a n c e w i t h the m a r k e d C h a t t - A h r l a n d Α-class b e h a v i o r of b o t h l a n t h a n i d e s a n d a c t i n i d e s , b u t h a v e b e e n m a d e b y r e a c t i o n of the t e t r a i o d i d e s w i t h the a p p r o p r i a t e c a t i o n i o d i d e i n m e t h y l c y a n i d e s o l u t i o n , the t e t r a p h e n y l - [ T h ( I V ) , U ( I V ) ] phenylmethylarsonium [Pa ( I V ) ]

and tri-

salts b e i n g the most stable h e x a i o d o

compounds. A l t h o u g h p l u t o n i u m t e t r a c h l o r i d e is u n k n o w n , its complexes oxygen

donor

Cs PuCl

6

2

l i g a n d s , s u c h as a m i d e s , c a n b e

with

prepared b y treating

w i t h a s o l u t i o n of the l i g a n d i n a n o n a q u e o u s solvent

(22);

some of t h e complexes f o r m e d b y the a c t i n i d e t e t r a c h l o r i d e s w i t h a m i d e s are s h o w n i n T a b l e I I . T h e Ν,Ν-dimethylaeetamide ( D M A )

complexes

a p p e a r to b e c h l o r i n e - b r i d g e d d i m e r s i n w h i c h the m e t a l e x h i b i t s 8coordination

whereas

(17),

complex T h C l

4

*4 D M A

n e p t u n i u m (70)

t h o r i u m forms

the

simple

T h e t h o r i u m (19),

(19).

8-coordinate

u r a n i u m (26),

and

t e t r a n i t r a t e complexes w i t h D M A , 2 M ( N G ) · 5 D M A , 3

4

are p r o b a b l y n i t r a t e - b r i d g e d d i m e r s analogous to the U C 1 c o m p l e x , b u t 4

the t h o r i u m a n d u r a n i u m t e t r a t h i o c y a n a t e complexes w i t h D M A (11, are 1:4 m o n o m e r s a n d are 8-coordinate l i k e the o c t a i s o t h i o c y a n a t o plexes

U n f o r t u n a t e l y , these t e t r a c h l o r i d e — D M A complexes

(75).

19) com­ de­

c o m p o s e i n a n x - r a y b e a m , a n d e v i d e n c e for t h e i r structures has b e e n obtained

by

indirect chemical methods

a n d is therefore

somewhat

speculative. Table II. MC1 MC1 2MC1 MC1 4

· 6CH CONH · 4CH CONH(CH ) · 5CH CON(CH ) · 4CH CON(CH ) 3

4

4

Actinide Tetrachloride-Acetamide 2

3

4

3

3

3

3

2

M = = M = M = M

3

2

Complexes

U , N p , P u (22) U (19) U , N p , P u (22) T h (19)

U n u s u a l coordination numbers have been

r e p o r t e d for d i m e t h y l

sulfoxide ( D M S O ) a n d hexamethylphosphoramide ( H M P A )

complexes

of some a c t i n i d e t e t r a h a l i d e s , n o t a b l y 7 - c o o r d i n a t i o n i n U C 1 · 3 D M S O 4

and T h B r

4

· 3 H M P A , a n d 9-coordination i n T h C l

a p p e a r to b e m o n o m e r i c (18).

4

Interestingly, T h B r

b e h a v e as a 1:1 electrolyte i n n i t r o m e t h a n e (18),

· 5 D M S O , a l l of w h i c h 4

* 6 D M S O appears to so that t h o r i u m m a y

1.

BAGNALL

Recent

5

Advances

w e l l b e 9-coordinate i n this c o m p l e x also. S o m e i n f r a r e d d a t a are s h o w n i n T a b l e I I I . C o m p l e x e s of t h e tetrahalides w i t h m e t h y l e n e b i s s u l f o x i d e s ( 5 0 ) , p h o s p h i n e oxides

( 5 5 ) a n d w i t h d i c a r b o x y l i c a c i d amides

(14)

h a v e also b e e n p r e p a r e d , b u t a l l a p p e a r to b e p o l y m e r i c a n d eis-chelates d o n o t seem to b e f o r m e d . Table III.

MX

4

^S = 0,

S = 0, cm.'

1

ThCl UC1 ThBr UBr

4

4

4

4

· 5DMSO · 3DMSO · 6DMSO · 6DMSO

4

4

4 4 4

· 2HMPA · 2HMPA · 3HMPA · 2HMPA · 2HMPA

cm:

1

108 103 102 112

942 947 948 938 P = 0,

ThCl ThBr ThBr UC1 UBr

(18)

Complexes with Oxygen Donors

Δνρ

cm:

1

o,

=

cm:

1

159 174 130 167 184

1042 1027 1071 1034 1017

Pentavalent State C o n s i d e r a b l e advances h a v e b e e n m a d e i n o u r k n o w l e d g e

of t h e

5-valent a c t i n i d e s , a g a i n m a i n l y i n t h e h a l i d e s a n d h a l o complexes. is n o w k n o w n , m a d e f r o m N p 0

*H

3

2

m e t a l w i t h m o l t e n l i t h i u m p e r c h l o r a t e (43). the most a t t e n t i o n , t h e p e n t a f l u o r i d e (94), bromide

a n d pentaiodide

(34)

oxygen

donors

(38),

5

P r o t a c t i n i u m has r e c e i v e d

as w e l l as t h e i r complexes a l l having been

i n v e s t i g a t e d i n t h e past f e w years. U n l i k e N b C l b r i d g e d p o l y m e r (47),

2

p e n t a c h l o r i d e (10, 36), p e n t a -

a n d t h e i r h a l o complexes,

chlorine-bridged dimers, P a C l

Np 0

0 (23) o r b y r e a c t i o n of n e p t u n i u m

5

with

thoroughly

a n d U C 1 , w h i c h are 5

appears to b e a n infinite l i n e a r c h l o r i n e -

5

its s y m m e t r y b e i n g a p p r o x i m a t e l y

O . 5h

T h e o x y h a l i d e s of t h e 5-valent a c t i n i d e s h a v e p r o v e d to b e of c o n ­ s i d e r a b l e interest, o x y g e n Pa OCl 2

(36),

8

b r i d g e d species

analogous to U O F 2

8

s u c h as P a O F 2

being reported.

(67)

spectra of t h e r a n g e of o x y g e n - b r i d g e d p r o t a c t i n i u m ( V ) (36)

8

and

(94)

T h e infrared oxychlorides

suggest that these represent successive stages i n t h e c h l o r i n a t i o n

of t h e p o l y m e r i c p e n t o x i d e ( F i g u r e 1 ) . T h e other k n o w n p r o t a c t i n i u m (V)

oxyhalides—PaOBr , PaOI , 3

nature (34),

Pa0 Br, 2

a n d P a 0 I — a r e similar i n 2

3

a n d U 0 B r (73)—which

m a y also b e p o l y m e r s .

2

Hydrated N p O F fluoride

3

b u t there are n o d a t a f o r t h e u r a n i u m a n a l o g — U O B r ( 8 5 )

3

(12)

has b e e n p r e p a r e d b y t h e a c t i o n of h y d r o g e n

o n the recently reported pentoxide, N p 0 2

5

(23, 43),

but N p F

5

itself has n o t y e t b e e n r e c o r d e d . Salts of t h e fluoro c o m p l e x ions M F " , M F 6

r e p o r t e d f o r P a ( V ) (5,7,

7

2

" , and M F

8

3

" have been

29, 30, 40, 66), U ( V ) (6, 56, 57, 81, 83, 84, 86,

6

LANTHANIDE/ACTINIDE

Pa O Cl

PaOClo

2

\

CI

CI

0< Pa

Pa

/

/ CI

\

CI

Pa OCl 2

Figure 1. 96), N p ( V )

\

CI

8

Pa (V)

and P u ( V )

(3)

oxygenated neptunium ( V )

4

CI

CI CI

s

CHEMISTRY

Oxychlorides

( δ ) , the last t w o b e i n g t h e first n o n -

and plutonium ( V )

compounds.

the p r e p a r a t i v e p r o c e d u r e s u s e d for u r a n i u m ( V )

fluoro

Some

complexes

of are

shown in Table I V . A recent s t u d y of the a l k a l i m e t a l / u r a n i u m fluoride c o m p l e x systems has s h o w n that K U F o , K U F , a n d K U F : i

3

7

a

c r y s t a l s y m m e t r y b e i n g unaffected b y the structure of K P a F 2

7

8

are i s o m o r p h o u s fluoride

(99),

i o n absences.

the The

has b e e n d e t e r m i n e d o n l y r e c e n t l y ( 3 9 ) , a n d it has

b e e n s h o w n that each p r o t a c t i n i u m a t o m is s u r r o u n d e d b y n i n e

fluorine

atoms i n w h a t is effectively a t r i g o n a l p r i s m w i t h three a d d e d e q u a t o r i a l fluorine

atoms; the P a F

fluorine

bridges.

groups are l i n k e d i n infinite chains b y

9

Salts of t h e analogous p r o t a c t i n i u m ( V ) ( 1 0 ) a n d u r a n i u m ( V )

two (20)

c h l o r o c o m p l e x ions, M C 1 " a n d M C 1 ~ , h a v e b e e n o b t a i n e d f r o m t h i o n y l 0

8

3

1.

BAGNALL

Recent

7

Advances

c h l o r i d e solutions of the 5-valent elements, b u t no h e p t a c h l o r o

complexes

h a v e b e e n i s o l a t e d . S i m i l a r l y , so f a r o n l y the h e x a b r o m o - a n d h e x a i o d o protactinates ( V )

have been obtained, prepared from methyl cyanide

solutions of the c o m p o n e n t s

(38).

C e s i u m h e x a c h l o r o u r a n a t e (V) has b e e n u s e d to p r e p a r e U C 1 * R P O 5

3

complexes b y r e a c t i o n w i t h the l i g a n d i n m e t h y l e n e d i c h l o r i d e (21), r e a c t i o n analogous to that u s e d to p r e p a r e P u C l corresponding P a C l

complexes,

4

complexes h a v e also b e e n m a d e (32);

5

d a t a are g i v e n i n T a b l e V . W h e r e a s N b C l of the l i g a n d , f o r m i n g N b O C l

some i n f r a r e d

· P h P O reacts w i t h a n excess

5

3

· 2 P h P O , the P a C l

3

a

a n d the

3

d o not. O n the other h a n d , n e i t h e r the N b C l

5

and U C 1

5

5

complexes

n o r PaCl» complexes w i t h

h e x a m e t h y l p h o s p h o r a m i d e ( H M P A ) react w i t h a n excess of l i g a n d . A l k a l i m e t a l dioxofluorides of the t y p e A M 0 F I

a n d A m (2, 64)

c o m p l e x salts of n e p t u n i u m ( V ) Table IV. MiUF

(M =

2

and americium ( V )

(24)

Np, Pu

(64)

( 2 5 ) are n o w

Preparation of U r a n i u m ( V ) Fluoro Complexes M = (a) N O , N 0 1

6

2

h a v e b e e n p r e p a r e d f r o m aqueous s o l u t i o n a n d c h l o r o

+

2

(b, c) L i , N a , K , R b , C s

+

+

+

+

+

+

(a) N O + U F - » N O U F (57) N O F + U F -> N O U F (57) 6

6

5

6

in 10-27M H F (b) ΜΨ + U F >MiUF 5

6

(6)

300°e. (c) ΜΨ 4- U F M iUF 2

M = K , Rb\ Cs 1

7

2ΜΨ + U F M iUF 3

5

+

300°C. >%MnJF +

3ΜΨ + U F

5

Na UF

2

3

Table V .

+

7

+

+ y M njF

NbCl, · Ph PO TaCl · Ph PO PaCl · Ph PO UC1 · Ph PO NbOCl · 2Ph PO 3

5

3

5

3

3

3

2

3

350°C. > M *UF 2

7

+

3

2

8

(84)

8

390°C. >Na UF 3

(86)

8

Infrared D a t a for M C l · P h P O Complexes 5

Ρ = 0,

3

e

350°C. >M !UF

+ y F

(83)

6

+

M i = Na , K , Rb , Cs

8

5

>MiUF

5

977 987 990 973 1167

cm:

1

3

AvP = O, 215 205 202 219 25

cm:

1

Reference 32 32 32 21 32, 44

8

LANTHANIDE/ACTINIDE

k n o w n ; the f o r m e r are salts of the " N p 0 0 2

f o r m a t i o n of C s N p O C l 2

i o n is m o r e

4

3

" and N p O C l

5

2

CHEMISTRY

" ions.

The

f r o m aqueous s o l u t i o n i n d i c a t e s that t h e N p 0

5

easily c h l o r i n a t e d t h a n h a d b e e n

suspected,

2

+

but further

c h l o r i n a t i o n results o n l y i n d i s p r o p o r t i o n a t i o n . " C s A m 0 0 " is isostruc3

t u r a l w i t h the n e p t u n i u m ( V ) c o m p o u n d

2

4

a n d there is some d o u b t

(25),

as to w h e t h e r these c o m p o u n d s are m o n o m e r i c or m o r e c o r r e c t l y f o r m u l a t e d as C s ( M 0 ) C l i i . 8

2

3

A f e w d e r i v a t i v e s of oxyanions h a v e also b e e n p r e p a r e d ;

protac-

t i n i u m ( V ) forms h e x a n i t r a t o complexes, P a ( N 0 ) ~ , b y r e a c t i o n of the 3

6

h e x a c h l o r o c o m p l e x w i t h d i n i t r o g e n p e n t o x i d e , i n contrast to n i o b i u m a n d tantalum w h i c h , under similar conditions, y i e l d only tetranitrato complexes, M O ( N 0 ) " ( 3 5 ) . 3

NpO(N0 ) 3

3

Neptunium (V)

4

h a v e also b e e n r e p o r t e d (71).

a n d selenato

complex

acids, H P a O ( S 0 ) 3

4

nitrates, N p 0 N 0 2

Protactinium ( V ) 3

and

3

sulfato-

and H P a O ( S e 0 ) , 3

4

have

3

b e e n o b t a i n e d f r o m aqueous s o l u t i o n ( 1 3 ) , b u t n o f u l l y s u l f a t e d or selen a t e d species h a v e b e e n r e c o r d e d .

Hexavalent State M u c h less w o r k has b e e n r e p o r t e d for the 6-valent elements as c o m p a r e d w i t h the v o l u m e of l i t e r a t u r e for the a c t i n i d e s i n l o w e r states. Np0

3

valence

H y d r a t e d n e p t u n i u m a n d p l u t o n i u m trioxides are n o w k n o w n , * H 0 and P u 0 2

3

·· ( 0 . 8 ) H O b e i n g r e a d i l y o b t a i n e d b y the a c t i o n 2

of o z o n e o n a n aqueous suspension of n e p t u n i u m ( V ) or p l u t o n i u m ( I V ) h y d r o x i d e s at 90 ° C . (23); at 18°C.

(23)

Np0

3

· 2 H 0 is o b t a i n e d i n a s i m i l a r m a n n e r 2

or b y o z o n e o x i d a t i o n of n e p t u n i u m ( V )

l i t h i u m - p o t a s s i u m n i t r a t e eutectic at 1 5 0 ° C .

i n a molten

(42).

A n o t h e r u n s u c c e s s f u l a t t e m p t has b e e n m a d e to p r e p a r e A m F , 6

fluorinating

Am 0 2

s u c h as N a U F 2

8

3

(63),

i n the presence of P t F NH UF 4

7

6

and N O U F

(102)

C o m p l e x e s of

(100). 7

(56)

by UF«

are n o w k n o w n ,

b u t the c o m p l e x i n g b e h a v i o r of n e p t u n i u m a n d p l u t o n i u m hexafluorides a n d u r a n i u m h e x a c h l o r i d e has scarcely b e e n i n v e s t i g a t e d . T h e most stable f o r m of the actinides ( V I ) M0

2

2 +

is the o x y g e n a t e d

ion

, a n d this t y p e of species has r e c e i v e d m u c h a t t e n t i o n .

A l t h o u g h a m e r i c i u m ( V I ) is r a p i d l y r e d u c e d to a m e r i c i u m ( I I I ) b y c h l o r i d e i o n i n aqueous s o l u t i o n , the i n s o l u b l e r e d C s A m 0 C l 2

o b t a i n e d w h e n the a m e r i c i u m ( V )

2

4

is r e a d i l y

c h l o r o c o m p l e x is t r e a t e d w i t h 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 ; the m e c h a n i s m of the r e a c t i o n is not yet k n o w n , b u t i t is not a result of d i s p r o p o r t i o n a t i o n Anhydrous neptunyl s o d i u m n e p t u n y l acetate Np0

3

fluoride, (52),

(25).

previously obtained b y

fluorinating

is m o r e c o n v e n i e n t l y m a d e b y t r e a t i n g

* H 0 w i t h l i q u i d b r o m i n e t r i f l u o r i d e at r o o m t e m p e r a t u r e , h y d r o 2

g e n fluoride at 3 0 0 ° C , or fluorine at 2 3 0 ° C , a n d e v e n b y v a c u u m d r y i n g a h y d r o f l u o r i c a c i d s o l u t i o n of N p 0

3

· H 0 (12), 2

f r o m w h i c h it appears

1.

BAGNALL

9

Recent Advances

that t h e n e p t u n y l c o m p o u n d is less s t r o n g l y h y d r a t e d t h a n u r a n y l

fluoride.

C o m p l e x e s of u r a n y l c h l o r i d e w i t h a v a r i e t y of o x y g e n d o n o r l i g a n d s c o n t i n u e to b e r e p o r t e d , n o t a b l y w i t h p h o s p h i n e oxides ( 5 5 ) , p y r i d i n e N - o x i d e s (27),

N , N - d i m e t h y l f o r m a m i d e (71),

acetamide ( 1 5 ) , a n d w i t h

the Ν,Ν,Ν',Ν'-tetramethyldiearboxylic a c i d a m i d e s (14),

t h e last b e i n g

m a i n l y p o l y m e r i c c o m p o u n d s . A f e w s i m i l a r c o m p l e x e s of u r a n y l b r o m i d e ( 54 ) a n d i o d i d e ( 71 ) are also k n o w n . I n c o n c l u s i o n , c o m p a r e d w i t h t h e ( i - t r a n s i t i o n elements a n d t h e l a n ­ t h a n i d e s , l i t t l e i n f o r m a t i o n is a v a i l a b l e o n t h e m a g n e t i c a n d s p e c t r a l properties of t h e a c t i n i d e s as a g r o u p , so t h a t there is c o n s i d e r a b l e scope f o r f u r t h e r w o r k i n this area. T h e s y m m e t r y properties o f / - o r b i t a l s are scarcely m e n t i o n e d i n t h e textbooks, a n d one m u s t search to find a n y t r e a t m e n t of t h e m i n t h e l i t e r a t u r e . T h i s reflects t h e c o m p l e x m a g n e t i c b e h a v i o r of m a n y a p p a r e n t l y m a g n e t i c a l l y d i l u t e a c t i n i d e complexes, together w i t h t h e o b v i o u s c o m p l e x i t y of t h e i r spectra, p a r t i c u l a r l y of species of h i g h c o o r d i n a t i o n n u m b e r a n d u n k n o w n , b u t p r o b a b l y l o w , symmetry.

I n this c o n n e c t i o n there is a n o b v i o u s n e e d f o r m o r e s t r u c ­

t u r a l w o r k , f o r i n n e a r l y e v e r y case c r y s t a l l o g r a p h i c d a t a are l a c k i n g a n d structures h a v e b e e n i n f e r r e d b y i n d i r e c t m e t h o d s .

Literature Cited (1) Asprey, L. B., Coleman, J. S., Reisfeld, M. J., ADVAN. CHEM. SER. 71, 122 (1967). (2) Asprey, L. B., Ellinger, F. H., Zachariasen, W. H., J. Am. Chem. Soc. 76, 5235 (1954). (3) Asprey, L. B., Keenan, T. K., Penneman, R. Α., Sturgeon, G. D., Inorg. Nucl. Chem. Letters 2, 19 (1966). (4) Asprey, L. B., Kruse, F. H.,J.Inorg. Nucl. Chem. 13, 32 (1960). (5) Asprey, L. B., Kruse, F. H., Penneman, R. Α.,J.Am. Chem. Soc. 87, 3518 (1965). (6) Asprey, L. B., Penneman, R. Α., Inorg. Chem. 3, 727 (1964). (7) Asprey, L. B., Penneman, R. Α., Science 145, 924 (1964). (8) Asprey, L. B., Sturgeon, G. D., Penneman, R. Α., J. Am. Chem. Soc. 87, 5803 (1965). (9) Baev, A. K., Novikov, G. I., Zh. Neorgan. Khim. 6, 2610 (1961). (10) Bagnall, K. W., Brown, D., J. Chem. Soc. 1964, 3021. (11) Bagnall, K. W., Brown, D., Colton, R., J. Chem. Soc. 1964, 2527. (12) Bagnall, K. W., Brown, D., Easey, J. F., J. Chem. Soc. (to be pub­ lished). (13) Bagnall, K. W., Brown, D., Jones, P. J.,J.Chem. Soc. 1965, 176. (14) Bagnall, K. W., Brown, D., Jones, P. J.,J.Chem. Soc. 1966, 741. (15) Bagnall, K. W., Brown, D., Jones, P. J.,J.Chem. Soc. (to be published). (16) Bagnall, K. W., Brown, D., Jones, P. J., du Preez, J. G. H., J. Chem. Soc. 1965, 350. (17) Bagnall, K. W., Brown, D., Jones, P. J., du Preez, J. G. H., J. Chem. Soc. 1965, 3594. (18) Bagnall, K. W., Brown, D., Jones, P. J., du Preez, J. G. H., J. Chem. Soc. 1966, 737. (19) Bagnall, K. W., Brown, D., Jones, P. J., Robinson, P. S., J. Chem. Soc. 1964, 2531.

10

LANTHANIDE/ACTINIDE CHEMISTRY

(20) Bagnall, K. W., Brown, D., du Preez, J. G. H., J. Chem. Soc. 1964, 2603. (21) Bagnall, K. W., Brown, D., du Preez, J. G. H., J. Chem. Soc. 1965, 5217. (22) Bagnall, K. W., Deane, A. M., Markin, T. L., Robinson, P. S., Stewart, Μ. Α. Α., J. Chem. Soc. 1961, 1611. (23) Bagnall, K. W., Laidler, J. B., J. Chem. Soc. 1964, 2693. (24) Bagnall, K. W., Laidler, J. B., J. Chem. Soc. 1966, 516. (25) Bagnall, K. W., Laidler, J. B., Stewart, M. A. A. (to be published). (26) Bagnall, K. W., Robinson, P. S., Stewart, Μ. Α. Α.,J.Chem. Soc. 1961, 4060. (27) Balakrishnan, P. V., Patil, S. K., Venkatasetty, Η. V., J. Inorg. Nucl. Chem. 28, 537 (1966). (28) Bauer, H., Blanc, J., Ross, D. L., J. Am. Chem. Soc. 86, 5125 (1964). (29) Brown, D., Easey, J. F., Nature 205, 589 (1965). (30) Brown, D., Easey, J. F., J. Chem. Soc. 1966, 254. (31) Brown, D., Easey, J. F., Jones, P. J., J. Chem. Soc. (to be published). (32) Brown, D., Easey, J. F., du Preez, J. G. H., J. Chem. Soc. 1966, 258. (33) Brown, D., Jones, P. J., Chem. Commun. 1966, 280. (34) Brown, D., Jones, P. J., J. Chem. Soc. 1966, 262. (35) Brown, D., Jones, P. J., J. Chem. Soc. 1966, 733. (36) Brown, D., Jones, P. J., J. Chem. Soc. 1966, 874. (37) Brown, D., Jones, P. J., J. Chem. Soc. (to to published). (38) Brown, D., Jones, P. J., private communication. (39) Brown, D., Smith, A. J., Chem. Commun. 1965, 554. (40) Bukhsh, M. N., Flegenheimer, J., Hall, F. M., Maddock, A. G., Miranda, C. Ferreira de, J. Inorg. Nucl. Chem. 28, 421 (1966). (41) Clark, R. J., Corbett, J. D., Inorg. Chem. 2, 460 (1963). (42) Cohen, D., Inorg. Chem. 2, 866 (1963). (43) Cohen, D., Walter, A. J., J. Chem. Soc. 1964, 2696. (44) Copley, D. B., Fairbrother, F., Thompson, Α., J. Less-Common Metals 8, 256 (1965). (45) Corbett, J. D., Druding, L. F., Burkhard, W. J., Lindahl, C. B., Discus­ sions Faraday Soc. 32, 79 (1961). (46) Cousins, D., Hart, Α., J. Inorg. Nucl. Chem., in press. (47) Dodge, R. P., Smith, G. S., Johnson, Q., Elson, R. W., U.S. Report UCRL-14581 (1966). (48) Druding, L. F., Corbett, J. D., J. Am. Chem. Soc. 83, 2462 (1961). (49) Druding, L. F., Corbett, J. D., Ramsey, Β. N., Inorg. Chem. 2, 869 (1963). (50) Du Preez, J. G. H., private communication. (51) Edelstein, N., Easley, W., McLaughlin, R., J. Chem. Phys. 44, 3130 (1966). (52) Fong, F. K., J. Chem. Phys. 41, 2291 (1964). (53) Fried, S., Nat. Nucl. Energy Ser., Div. IV, 14 A, 471 (1954). (54) Gans, P., Ph.D. Thesis, London (1964). (55) Gans, P., Smith, B. C., J. Chem. Soc. 1964, 4172. (56) Geichman, J. R., Smith, Ε. Α., Ogle, P. R., Inorg. Chem. 2, 1012 (1963). (57) Geichman, J. R., Smith, Ε. Α., Trond, S. S., Ogle, P. R., Inorg. Chem. 1, 661 (1962). (58) Green, J. L., U.S. Report UCRL-16516 (1965). (59) Gut, R., Gruen, D. M., J. Inorg. Nucl. Chem. 21, 259 (1961). (60) Hulet, Ε. K., Hoff, R. W., Evans, J. E., Lougheed, R. W., Phys. Rev. Letters 13, 343 (1964).

1. BAGNALL

Recent Advances

11

(61) Joesten, M . D., Jacob, R. Α., ADVAN. CHEM. SER. 71, 13 (1967). (62) Jørgensen, C. K., Proc. Conf. Rare Earth Res., 5th, Ames, Iowa, 1965, Paper No. CERI-TIC-P99. (63) Katz, S., Inorg. Chem. 3, 1598 (1964). (64) Keenan, T. K., Inorg. Chem. 4, 1500 (1965). (65) Keller, C., Schmutz, Η., Z. Naturforsch. 19B, 1080 (1964). (66) Keller, O. L., Chetham-Strode, Α., Proc. Colloque Phys.-chim. Protactinium1965,119 (67) Kirslis, S. S., McMillan, T. S., Bernhardt, Η. Α., U.S. Report K-567 (1950). (68) Kiss, Z. J., Yocom, P. N.,J.Chem. Phys. 41, 1511 (1964). (69) Korshunov, B. G., Drobot, D. V., Zh. Neorgan. Khim. 9, 222 (1964). (70) Laidler, J. B.,J.Chem. Soc. 1966, 780. (71) Lamisse, M., Heimburger, R., Rohmer, R., Compt. rend. 258, 2078 (1964). (72) Leary, J. Α., U.S. Report LA-2661 (1962). (73) Levet, J. C., Compt. rend. 260, 4775 (1965). (74) McClure, D. S., Kiss, Z., J. Chem. Phys. 39, 3251 (1963). (75) Markov, V. P., Traggeim, Ε. N., Zh. Neorgan. Khim. 6, 2316 (1961). (76) Moeller, T., Galasyn, V., J. Inorg. Nucl. Chem. 12, 259 (1960). (77) Moeller, T., Vicentini, G., J. Inorg. Nucl. Chem. 27, 1477 (1965). (78) Morozov, I. S., Ionov, V. I., Korshunov, B. G., Zh. Neorgan. Khim. 4, 1457 (1959). (79) Muetterties, E. L., Wright, C. M.,J.Am. Chem. Soc. 87, 4706 (1965). (80) Novikov, G. I., Polyachenok, O. G., Frid, S. Α., Zh. Neorgan. Khim. 9, 472 (1964). (81) Penneman, R. Α., Asprey, L. B., Sturgeon, G., J. Am. Chem. Soc. 84, 4608 (1962). (82) Penneman, R. Α., Keenan, T. K., Asprey, L. B., ADVAN. CHEM. SER. 71, 248 (1967). (83) Penneman, R. Α., Kruse, F. H., George, R. S., Coleman, J. S., Inorg. Chem. 3, 309 (1964). (84) Penneman, R. Α., Sturgeon, G. D., Asprey, L. B., Inorg. Chem. 3, 126 (1964). (85) Prigent, J., Ann. Chim. (Paris), 15, 65 (1960). (86) Rüdorff, W., Leutner, H., Ann. 632, 1 (1960). (87) Ryan, J. L., ADVAN. CHEM. SER. 71, 331 (1967). (88) Ryan, J. L., Jørgensen, C. K., Mol. Phys. 7, 17 (1963). (89) Ryan, J. L., Jørgensen, C. K., Cyanamid European Research Institute, Geneva, Rep. CERI-TIC-P95 (1965). (90) Sallach, R. Α., Corbett, J. D., Inorg. Chem. 2, 457 (1963). (91) Scaife, D. E., Wylie, A. W., J. Chem. Soc. 1964, 5450. (92) Soriano, J., Givon, M., Shamir, J., Inorg. Nucl. Chem. Letters 2, 13 (1966). (93) Soriano, J., Marcus, Y., Inorg. Chem. 3, 901 (1964). (94) Stein, L., Inorg. Chem. 3, 995 (1964). (95) Stevens, R. E., J. Inorg. Nucl. Chem. 27, 1873 (1965). (96) Sturgeon, G. D., Penneman, R. Α., Kruse, F. H., Asprey, L. B., Inorg. Chem. 4, 748 (1965). (97) Sun, I. C., Morozov, I. S., Zh. Neorgan. Khim. 3, 1914 (1958). (98) Sung, Yu-Lin, Novikov, G. I., Zh. Neorgan. Khim. 8, 700 (1963). (99) Thoma, R. E., Friedman, Η. Α., Penneman, R. Α., J. Am. Chem. Soc. 88, 2046 (1966). (100) Thoma, R. E., Insley, H., Hebert, G. M., Inorg. Chem. 5, 1222 (1966). (101) Tsujimura, S., Cohen, D., Chernick, C. L., Weinstock, B., J. Inorg. Nucl. Chem. 25, 226 (1963).

12

LANTHANIDE/ACTINIDE CHEMISTRY

(102) Volavsek, B., Croat. Chem. Acta. 33, 181 (1961). (103) Weigel, F., Proc. Conf. Rare Earth Res., 5th, Ames, Iowa, 1965, Paper No. 650804-7 (Nucl Sci. Abstr. 19, 43988 (1965) ). (104) Zalkin, Α., Forrester, J. D., Templeton, D. H., Inorg. Chem. 3, 639 (1964). RECEIVED August 7, 1966.