Alkaline Earth Metals

(1)

Alkaline Earth Metals

P. EHRLICH

Berylliu m Be

On a l a b o r a t o r y s c a l e , b e r y l l i u m i s p r e p a r e d by e l e c t r o l y s i s of a m i x t u r e of m o l t e n b e r y l l i u m f l u o r i d e and a l k a l i o r a l k a l i n e e a r t h f l u o r i d e s . The p r o d u c t o b t a i n e d i s 99.7% p u r e ; t h e c o m m e r c i a l m a t e r i a l o b t a i n e d by t h e s a m e m e t h o d i s < 99%. I n d u s t r i a l e l e c t r o l y s i s of b e r y l l i u m c h l o r i d e - a l k a l i c h l o r i d e m e l t s y i e l d s b e r y l l i u m with a p u r i t y u s u a l l y g r e a t e r t h a n 99.8%.

V e r y high p u r i t y Be i s o b t a i n e d by K r o l P s p r o c e d u r e ( w h i c h i s a m o d i f i c a t i o n of S l o m a n ' s m e t h o d ) w h i c h c o n s i s t s in v a c u u m d i s t i l l a - tion in t h e a p p a r a t u s shown in F i g . 2 5 2 . T h e r e l a t i v e l y i m p u r e b e r y l l i u m i s p l a c e d in a BeO c r u c i b l e and induction h e a t e d , and i t s v a p o r i s c o n d e n s e d in a c o n d e n s a t i o n hood. T h e l a t t e r i s t i g h t l y joined to t h e c r u c i b l e , but h a s an o p e n i n g on t o p , s o t h a t t h e c o u r s e of t h e d i s t i l l a t i o n m a y b e o b s e r v e d t h r o u g h a q u a r t z p e e p h o l e at t h e top of t h e a p p a r a t u s . T h e BeO c r u c i b l e i s e m b e d d e d in s i n t e r e d , p o w d e r e d BeO,which fills a r e t a i n i n g v e s s e l of s i n t e r e d a l u m i n a .

T h e whole a s s e m b l y i s p l a c e d in a q u a r t z t u b e which i s c l o s e d off on top by a s p e c i a l w a t e r - c o o l e d a d a p t e r . T h i s m e t a l l i c a d a p t e r m a y be m a d e e i t h e r of c o m p r e s s e d m e t a l p o w d e r o r of b r o n z e i m p r e g n a t e d with tin u n d e r v a c u u m . It i s s e a l e d to t h e q u a r t z t u b e with h i g h - v a c u u m s i l i c o n e g r e a s e . T h e a p p a r a t u s i s c o n n e c t e d to a h i g h - v a c u u m p u m p by m e a n s of a flexible t o m b a c t u b e . T h e d i s t i l l a t i o n r e q u i r e s a v a c u u m of < 10 "³ m m

T h e d i s t i l l a t i o n of c r u d e b e r y l l i u m i s c o n n e c t e d with c e r t a i n difficulties s i n c e t h e m e t a l o c c l u d e s the e l e c t r o l y t e and a l k a l i n e e a r t h m e t a l s . T h e s e m a y c a u s e bubbling and s p a t t e r i n g of t h e m e t a l l i c m e l t d u r i n g the d i s t i l l a t i o n . T h e r e f o r e , p r e l i m i n a r y d e - g a s s i n g i s c a r r i e d out without t h e c o n d e n s a t i o n h o o d until g a s e v o l u t i o n c e a s e s . After c o o l i n g , t h e c o n d e n s a t i o n hood i s i n s t a l l e d , and a f t e r high v a c u u m h a s b e e n r e s t o r e d t h e d i s t i l l a t i o n i s c a r r i e d out at a t e m p e r a t u r e of 1400 to 1500° C. If b e r y l l i u m flakes a r e u s e d , t h e y a r e f i r s t c o m p r e s s e d and m e l t e d . T h i s m e l t m a y b e

887

(2)

8 8 8 P. E H R L I C H p e e p h o l e

c o o l i n g water

induction Q | | c o i l ^

high v a c u u m

quartz tube

c o o l i n g air condensation hood

of BeO

sintered BeO crucible fro

- corundum crucible

powdered BeO

F i g . 252. H i g h - v a c u u m d i s t i l l a t i o n of b e r y l l i u m .

d i s t i l l e d at o n c e s i n c e it d o e s not c o n t a i n s a l t o c c l u s i o n s . T h e d i s t i l l a t i o n i s c o m p l e t e in about 20 m i n u t e s . The r u n i s e n d e d when about 75% of t h e c h a r g e h a s d i s t i l l e d . Depending on the o p - e r a t i n g t e m p e r a t u r e , t h e b e r y l l i u m c o l l e c t s on t h e hood in t h e f o r m of l a r g e g l o b u l e s o r an i n c r u s t a t i o n ( d e n d r i t e s ) . T h e d e g r e e of p u r i t y s h o u l d e x c e e d 99.97%, n e g l e c t i n g t h e s m a l l q u a n t i t y of oxygen t h a t m a y be p r e s e n t .

T h e r e c o v e r y of Be c o m p o u n d s f r o m g a d o l i n i t e is d e s c r i b e d in t h e s e c t i o n on s c a n d i u m , y t t r i u m and r a r e e a r t h m e t a l s .

PROPERTIES:

A t o m i c weight 9.02.

M.p. 1280°C, b . p . 2970°C; c r y s t a l l i z e s in s t r u c t u r e type A 3 ; b r i t t l e at r o o m t e m p e r a t u r e , d u c t i l e at r e d h e a t .

In c o n t a c t with w a t e r , Be b e c o m e s c o v e r e d with a thin oxide l a y e r but i s not a t t a c k e d f u r t h e r ; h o w e v e r , it d i s s o l v e s v e r y v i g o r o u s l y in d i l u t e a c i d s .

REFERENCES:

H. F u n k , Die D a r s t e l l u n g d e r M e t a l l e i m L a b o r a t o r i u m [The P r e p - a r a t i o n of M e t a l s in t h e L a b o r a t o r y ] , S t u t t g a r t , 1938, p . 28.

W. K r o l l , B e r y l l i u m , in: A. E. van A r k e l , R e i n e M e t a l l e [ P u r e M e t a l s ] , B e r l i n , 1939, p . 99.

W. K r o l l , M e t a l l w i r t s c h a f t 1 3 , 725 (1934); M e t a l . Ind. 4 7 , 29 (1935).

H. A. S l o m a n , J. Inst. Met. 4 4 , 365 (1932).

(3)

Berylliu m Chlorid e

BeCI2

L BeO + C + Cl² = BeCl² + CO

25.0 12.0 70.9 79.9 28.0

B e r y l l i u m h a l i d e s do not a t t a c k P y r e x g l a s s if t h e t e m p e r a t u r e i s c a r e f u l l y c o n t r o l l e d . T h e r e f o r e , only t h e a c t u a l r e a c t i o n a p p a r a t u s m u s t b e of q u a r t z , while v a c u u m s u b l i m a t i o n and b o t t l i n g m a y b e c a r r i e d out in P y r e x g l a s s .

A s shown in F i g . 2 5 3 , t h e a p p a r a t u s c o n s i s t s of a l a r g e q u a r t z t u b e A ( 2 5 - m m . d i a m e t e r , 400 m m . long), which i s c o n n e c t e d with a g a s d r y i n g s y s t e m by m e a n s of a l a r g e g r o u n d g l a s s joint; i t s o t h e r end i s c o n n e c t e d , by m e a n s of a s m a l l g r o u n d g l a s s joint a , with a P y r e x a p p a r a t u s . T h e l a t t e r c o n s i s t s of s e v e r a l c y l i n d r i c a l c h a m b e r s B, C, D and Ε which s e r v e a s r e c e i v e r s and r e s u b l i - m a t i o n v e s s e l s for t h e h a l i d e . C h a m b e r Ώ i s fitted with a s i d e t u b e c l o s e d off by a b r e a k a b l e bulb. A s y s t e m of s t o r a g e b u l b s

(1, 2, 3 , 4) i s l a t e r s e a l e d to t h e s i d e a r m .

F i g . 2 5 3 . P r e p a r a t i o n and s u b l i m a t i o n of b e r y l l i u m c h l o r i d e .

An i n t i m a t e b l e n d of 3.5 g. of BeO and 2.5 g. of c h a r c o a l m a d e f r o m c a l c i n e d s u g a r i s c h a r g e d into a q u a r t z b o a t s , which i s t h e n p u s h e d into t u b e A. After r e m o v a l of w a t e r and o t h e r i m p u r i t i e s a d s o r b e d on the c a r b o n by h e a t i n g to about 900°C in a s t r e a m of Ν², t h e n i t r o g e n i s r e p l a c e d by CI² and t h e r e a c t i o n t e m p e r a t u r e i s a d j u s t e d to 700°C. T h e s u b l i m a t e of B e C l², which c o l l e c t s o v e r a p e r i o d of s e v e r a l h o u r s , f o r m s beautiful w h i t e , m a t t e d c r y s t a l s in t h e r e a r s e c t i o n of t u b e A. After c o m p l e t i o n of t h e r e a c t i o n , p u r e N² i s r e i n t r o d u c e d and t h e P y r e x a p p a r a t u s is c o n n e c t e d to joint a. T h e l a t t e r i s not g r e a s e d s i n c e no v a c u u m i s a p p l i e d . By p r o p e r p o s i t i o n i n g of t h e t u b u l a r f u r n a c e , t h e h a l i d e r e s u b l i m e s and d e p o s i t s in the f i r s t c h a m b e r B⁹ while l e a v i n g a r e s i d u e in A. The s u b l i m a t i o n t a k e s p l a c e at an a d e q u a t e r a t e at 380°C. J o i n t a i s t h e n m e l t - s e a l e d at i t s n a r r o w e s t p o i n t a n d t h e a p p a r a t u s is c o n n e c t e d to t h e h i g h - v a c u u m p u m p . A f o r e r u n i s t h e n s u b l i m e d into t h e f o u r t h c h a m b e r Ε by shifting t h e f u r n a c e .

(4)

8 9 0 P . E H R L I C H

The f u r n a c e i s t h e n shifted b a c k and t h e bulk of t h e m a t e r i a l i s s u b l i m e d into c h a m b e r 0. T h i s m a y b e done at 330°C, p r o v i d e d a high v a c u u m i s m a i n t a i n e d . C h a m b e r B⁹ s t i l l containing a r e s i d u e , i s r e m o v e d by s e a l i n g off.

T h e m a t e r i a l i s t h e n r e s u b l i m e d f r o m 0 into Ό. T h u s , only c h a m b e r Ώ⁹ c o m p l e t e l y e v a c u a t e d and s e a l e d off on both s i d e s , r e m a i n s of t h e e n t i r e P y r e x a p p a r a t u s . T h e v a c u u m p u m p m u s t o p e r a t e c o n t i n u o u s l y d u r i n g t h e s e s u b l i m a t i o n s s i n c e it h a s b e e n found i m p o s s i b l e to c a r r y t h e m out in an e v a c u a t e d and s e a l e d a p p a r a t u s . Small a m o u n t s of g a s a r e d e s o r b e d f r o m t h e g l a s s w a l l s , t h u s d e c r e a s i n g t h e v a c u u m . T h i s in t u r n r a i s e s t h e s u b l i m a t i o n t e m p e r a t u r e . At t h e s e h i g h e r t e m p e r a t u r e s , t r a c e s of B e C l² r e a c t with t h e g l a s s , f o r m i n g BeO + S i C l⁴, which a g a i n l e a d s to d e t e r i o r a t i o n of the v a c u u m until t h e s u b l i m a t i o n c e a s e s a l t o g e t h e r and liquid SiCl⁴ f o r m s at t h e c o l d e s t s p o t . It i s b e s t to c a r r y out t h e e n t i r e o p e r a t i o n without i n t e r r u p t i o n o v e r a p e r i o d of about 30 h o u r s .

To b o t t l e B e C l², a 1 0 - c m . - l o n g g l a s s t u b e i s a t t a c h e d to t h e s i d e tube of Ώ, a s m a l l g l a s s - c o v e r e d s t e e l r o d b is p u s h e d in, a n d finally the f o u r - b u l b a s s e m b l y i s s e a l e d on. T h e a p p a r a t u s i s c o n n e c t e d to t h e v a c u u m p u m p via a g r o u n d - g l a s s joint, a cold t r a p and a s t o p c o c k . After t h o r o u g h h e a t i n g , t h e s t o p c o c k i s c l o s e d , t h e a p p a r a t u s is d e t a c h e d f r o m t h e p u m p , and t h e l i t t l e g l a s s bulb i s b r o k e n by moving b with a m a g n e t . T h e b e r y l l i u m c h l o r i d e i s s u b l i m e d into t h e individual b u l b s at t h e h i g h e s t v a c u u m o b t a i n a b l e , w h i l e t h e t r a p i s c o o l e d with liquid n i t r o g e n ; t h i s o p e r a t i o n r e q u i r e s about four h o u r s p e r b u l b .

Other preparative methods: The r e a c t i o n of b e r y l l i u m with C l² and HCl (II) o r t h e t r e a t m e n t of BeO with C C 1⁴ (III) m a y a l s o b e r e c o m m e n d e d .

PROPERTIES:

Snow-white c r y s t a l s o r c r y s t a l l i n e m a s s . M . p . 405°C, b . p . 488°C;

d 1.90. E x t r e m e l y h y g r o s c o p i c ; d i s s o l u t i o n in w a t e r i s h i g h l y e x o t h e r m i c . The s o l u t i o n i s s t r o n g l y a c i d due to h y d r o l y t i c c l e a v a g e . On e v a p o r a t i o n , t h e h y d r a t e B e C l² · 4 H²0 c r y s t a l l i z e s in m o n o c l i n i c , d e l i q u e s c e n t p l a t e l e t s if t h e h y d r o l y s i s i s d e p r e s s e d b y t h e addition of h y d r o c h l o r i c acid; o t h e r w i s e , b a s i c c h l o r i d e s p r e c i p i t a t e . A n h y d r o u s B e C l² i s r e a d i l y s o l u b l e in a l c o h o l and

e t h e r .

REFERENCES:

I. O. H o n i g s c h m i d and T . J o h a n n s e n , Z . N a t u r f o r s c h . 1, 650 (1946); H. R e m y , L e h r b u c h d. a n o r g . C h e m . [ T e x t b o o k of I n o r g a n i c C h e m i s t r y ] v o l . I, L e i p z i g 1950, p . 2 5 7 .

(5)

Π. O. Rahlfs a n d W. F i s c h e r , Z . a n o r g . a l l g . C h e m . 2 1 1 , 349 (1933).

ΠΙ. J . B e s s o n , C o m p t e s R e n d u s Hebd. S e a n c e s A c a d . S c i . 2 1 4 , 861 (1942).

Berylliu m Bromid e BeBr²

I. BeO + C + Br² = BeBr² + CO

25.0 12.0 159.8 168.8 28.0

T h e d i r e c t i o n s for t h e p r e p a r a t i o n of B e C l² apply with t h e following m o d i f i c a t i o n s : a n i t r o g e n s t r e a m c h a r g e d with B r² v a p o r i s p a s s e d o v e r t h e B e O + C m i x t u r e a t 1200°C. T h i s m i x t u r e i s v e r y c o r r o s i v e t o q u a r t z . T h e f i r s t s u b l i m a t i o n m a y b e c o m p l e t e d sufficiently r a p i d l y a t a t m o s p h e r i c p r e s s u r e a t 360°C; f o r t h e following s u b l i m a t i o n s a t e m p e r a t u r e of 310°C i s sufficient, p r o vided a high v a c u u m i s m a i n t a i n e d .

II. Be + Br² = BeBr²

9.0 159.8 168.8

To p r e p a r e B e B r² d i r e c t l y f r o m t h e e l e m e n t s , b r o m i n e i s e v a p o r a t e d in a flask b y h e a t i n g with a n i n f r a r e d l a m p a n d p a s s e d in a s t r e a m of a r g o n o v e r Be p o w d e r in a q u a r t z t u b e a t a t e m p e r a t u r e of 550°C. T h e e n d of t h e t u b e p r o t r u d e s into a cold r e c e i v e r c o n s i s t i n g of a l a r g e g l a s s c y l i n d e r . In o r d e r t o avoid plugging of t h e t u b e i n t h e t r a n s i t i o n z o n e , t h e i n t e r i o r of t h e t u b e i s h e a t e d with a n e l e c t r i c a l winding t o 450-500°C; t h e winding i s s u r r o u n d e d b y a s m a l l q u a r t z t u b e which i s s e a l e d a t o n e e n d . T h i s q u a r t z t u b e e x t e n d s f r o m t h e r e c e i v e r into t h e h o t z o n e of t h e r e a c t i o n t u b e . T h e r e c e i v e r i s s e p a r a t e d f r o m t h e a t m o s p h e r e b y s e v e r a l w a s h b o t t l e s , which a l s o s e r v e a s bubble c o u n t e r s .

T h e a n h y d r o u s b r o m i d e p r o d u c t i s t r a n s f e r r e d t o s t o r a g e v e s s e l s u n d e r an i n e r t g a s b l a n k e t . T h e y i e l d i s 2 0 0 - 2 5 0 g . in s i x h o u r s .

PROPERTIES:

L o n g , white n e e d l e s . M . p . 488°C, with s u b l i m a t i o n beginning a t 360°C; d 3 . 4 7 . V e r y h y g r o s c o p i c ; l a r g e h e a t of s o l u t i o n . T h e t e t r a h y d r a t e c r y s t a l l i z e s a s r o d - s h a p e d , h y g r o s c o p i c c r y s t a l s when t h e B e B r² s o l u t i o n i s e v a p o r a t e d t o a s i r u p y c o n s i s t e n c y . G a s e o u s H B r m u s t b e a d d e d t o t h e s o l u t i o n t o avoid p r e c i p i t a t i o n of b a s i c s a l t s due to h y d r o l y s i s .

(6)

8 9 2 P. E H R L I C H

REFERENCES:

I. O. H o n i g s c h m i d and T . J o h a n n s e n , Z. N a t u r f o r s c h . 1, 650 (1946).

II. G. B. Wood and A. B r e n n e r , J . E l e c t r o c h e m . Soc. 104, 29 (1957); s e e a l s o O. Rahlfs and W. F i s c h e r , Z. a n o r g . a l l g . C h e m . 2 1 1 , 349 (1933).

Berylliu m Iodid e Bel²

I. Be + I² = Bel²

9.0 253.8 262.8

B e r y l l i u m iodide is f o r m e d via t h e r e a c t i o n of g a s e o u s I² (or a m i x t u r e of p u r e H^s and Ig) with m e t a l l i c Be in a q u a r t z t u b e at dull r e d h e a t . It i s b e s t to w o r k in a s e a l e d t u b e ; h o w e v e r , the m e t a l and t h e s o l i d iodine s h o u l d not b e b l e n d e d with e a c h o t h e r , s i n c e t h i s m a y c a u s e b u r s t i n g of t h e t u b e d u r i n g h e a t i n g . T h e m e t a l i s i n s e r t e d s e p a r a t e l y in a g l a s s c o n t a i n e r s o t h a t it c o m e s in c o n t a c t only with the I² v a p o r . After 2 - 3 d a y s at 480°C, l i t t l e u n r e a c t e d i o d i n e r e m a i n s . T h u s , e a c h t u b e c o n t a i n s 4 g. of Be (1.8 g. e x c e s s ) and 63 g. of i o d i n e . T h e s u b s e q u e n t s u b l i m a t i o n , which g i v e s a p u r e white p r o d u c t , i s c a r r i e d out a s d e s c r i b e d for B e C l²; h o w e v e r , it i s p r e f e r a b l e to w o r k in a l l - q u a r t z e q u i p m e n t in v i e w of t h e h i g h e r t e m p e r a t u r e s .

Π· Be²C + 2 I² = 2BeI² + C

30.0 507.7 525.7 12.0

Be²C + 4 HI = 2BeI² + CH⁴

30.0 511,7 525.7 16.0

T h e iodide c a n n o t be p r e p a r e d in t h e s a m e fashion a s t h e c h l o r i d e , i . e . , b y p a s s i n g a n i t r o g e n s t r e a m c h a r g e d with I² o v e r a m i x t u r e of BeO + C; B e²C i s r e q u i r e d a s t h e s t a r t i n g m a t e r i a l .

In a q u a r t z tube at about 700°C, B e²C i s a l l o w e d to r e a c t with c a r e f u l l y p u r i f i e d and d r i e d HI o r with a h y d r o g e n s t r e a m c o n t a i n ing 1² v a p o r . The s u b s e q u e n t p u r i f i c a t i o n b y s u b l i m a t i o n i s t h e s a m e a s t h a t d e s c r i b e d a b o v e for B e C l².

PROPERTIES:

White n e e d l e s . M . p . 480°C, b . p . 488°C. V e r y h y g r o s c o p i c ; h y d r o l y z e s v i g o r o u s l y , evolving HI.

(7)

REFERENCES:

I. G. B. Wood and A. B r e n n e r , J . E l e c t r o c h e m . Soc. 104, 29 (1957); s e e a l s o O. Rahlfs and W. F i s c h e r , Z . a n o r g . a l l g . C h e m . 2 1 1 , 349 (1933).

Π. P . L e b e a u , Ann. C h i m . [7] 1 6 , 4 7 6 , 4 9 0 (1899); C. M e s s e r k n e c h t and W. B i l t z , Z. a n o r g . a l l g . C h e m . 148, 152 (1925).

Berylliu m Oxid e an d Berylliu m Carbonat e BeO, BeCOs

B e C 03 = BeO + C 02

69.0 25.0 44.0

C o m m e r c i a l b e r y l l i u m c a r b o n a t e , w h i c h u s u a l l y c o n t a i n s m o r e t h a n 1% of i m p u r i t i e s , i s m i x e d in a p l a t i n u m v e s s e l with h o t , t w i c e - d i s t i l l e d a c e t i c a c i d a n d t h e hot s o l u t i o n i s f i l t e r e d t h r o u g h a p l a t i n u m Gooch c r u c i b l e . T h e b a s i c a c e t a t e s e p a r a t e s a s fine c r y s t a l s on r a p i d c h i l l i n g ; it i s r e c r y s t a l l i z e d f r o m g l a c i a l a c e t i c a c i d t h r e e t i m e s . E a c h t i m e , t h e s a l t i s s e p a r a t e d by m e a n s of a p l a t i n u m b a s k e t c e n t r i f u g e . After t h i s p r e l i m i n a r y p u r i f i c a t i o n , t h e a c e t a t e i s s u b l i m e d at a t e m p e r a t u r e of 250°C in a l a r g e - d i a m e t e r g l a s s tube with a s t r e a m of p u r e , d r y a i r flowing t h r o u g h t h e a p p a r a t u s . T h e s u b l i m a t e i s h e a t e d in a d e g a s s e d P y r e x f l a s k with p u r e c o n c e n t r a t e d n i t r i c a c i d to c o n v e r t it to t h e n i t r a t e . T h e l a t t e r m a y b e c a l c i n e d to t h e o x i d e at 1100°C; h o w e v e r , t h e o x i d e t h u s p r e p a r e d a l w a y s c o n t a i n s about 0.35 m l . of g a s ( N², O^a) p e r g r a m of s u b s t a n c e .

V e r y p u r e oxide m a y b e o b t a i n e d when t h e b e r y l l i u m n i t r a t e p r e p a r e d a s d e s c r i b e d a b o v e i s r e c o n v e r t e d t o t h e c a r b o n a t e . An a c i d s o l u t i o n of t h e n i t r a t e i s e v a p o r a t e d in a p l a t i n u m d i s h t o r e m o v e e x c e s s a c i d , t h e r e s i d u e i s d i s s o l v e d in s o m e w a t e r , a n d enough d i s t i l l e d a m m o n i u m c a r b o n a t e s o l u t i o n i s added t o r e d i s - s o l v e t h e i n i t i a l l y p r e c i p i t a t e d b e r y l l i u m c a r b o n a t e a n d g i v e a c l e a r s o l u t i o n . T h e s o l u t i o n i s t h e n e v a p o r a t e d in a p l a t i n u m d i s h until a l l t h e b e r y l l i u m c a r b o n a t e h a s s e p a r a t e d a s a c o a r s e p r e c i p i t a t e . After t h o r o u g h w a s h i n g with p u r e w a t e r and t h e n with f r e s h l y d i s t i l l e d a l c o h o l , t h e p r o d u c t i s d r i e d and finally c a l c i n e d to t h e o x i d e in a p l a t i n u m v e s s e l p l a c e d in an e l e c t r i c f u r n a c e a t 900°C.

PROPERTIES:

W h i t e , l o o s e p o w d e r . M . p . 2 5 3 0 ° C ; d 2 9 . V e r y s p a r i n g l y s o l u b l e in w a t e r (about 0.20 g. p e r l i t e r ) . Its s o l u b i l i t y in a c i d s d e p e n d s upon t h e c a l c i n a t i o n t e m p e r a t u r e ; d i s s o l v e s m o s t r e a d i l y in h y d r o f l u o r i c a c i d . C r y s t a l l i z e s in s t r u c t u r e t y p e B 4 .

(8)

8 9 4 P . E H R L I C H

REFERENCE:

O. H o n i g s c h m i d and T . J o h a n n s e n , Z . N a t u r f o r s c h . 1, 650 (1946).

Berylliu m Hydroxid e Be(OH)²

Two c r y s t a l l i n e m o d i f i c a t i o n s m a y b e o b t a i n e d , t h e m e t a s t a b l e a - B e ( O H )² and t h e s t a b l e / ? - B e ( O H )².

a-Be(OH)²

T h e a f o r m i s t h e p r i m a r y p r o d u c t of aging of a m o r p h o u s b e r y l l i u m h y d r o x i d e , which i s o b t a i n e d by t h e p r e c i p i t a t i o n of a b e r y l l i u m s a l t s o l u t i o n with a m m o n i a in t h e a b s e n c e of C 0³; o - B e ( O H )² i s t h e n o b t a i n e d by p r o l o n g e d h e a t i n g (about 24 h o u r s ) of t h e a m o r p h o u s p r e c i p i t a t e with 10% a m m o n i u m h y d r o x i d e s o l u t i o n .

A v e r y p u r e m a t e r i a l m a y b e o b t a i n e d by e l e c t r o d i a l y s i s of a m o r p h o u s b e r y l l i u m h y d r o x i d e . T h i s i s a s l o w p r o c e d u r e and t a k e s s e v e r a l d a y s .

/?-Be(OH)²

The b e t a m o d i f i c a t i o n i s b e s t p r e p a r e d by s l o w h y d r o l y s i s of s o d i u m b e r y l l a t e . Boiling ION NaOH s o l u t i o n i s s a t u r a t e d with p u r e , a m o r p h o u s b e r y l l i u m h y d r o x i d e until a p e r m a n e n t t u r b i d i t y i s j u s t e v i d e n t . A s a n d y , finely c r y s t a l l i n e p r o d u c t s e p a r a t e s upon s l o w c o o l i n g . U n d e r t h e m i c r o s c o p e , t h e c r y s t a l s a p p e a r a s beautiful, r e g u l a r double p y r a m i d s . T h e y m a y b e p u r i f i e d , without c h a n g i n g t h e i r a p p e a r a n c e , with w a r m w a t e r until t h e y no l o n g e r s h o w an a l k a l i n e r e a c t i o n ; t h e c r y s t a l s a r e t h e n d r i e d at 80°C.

T h e s a m e m o t h e r l i q u o r m a y b e r e u s e d s e v e r a l t i m e s in t h e s a t u r a t i o n and c r y s t a l l i z a t i o n s e q u e n c e .

PROPERTIES:

F o r m u l a weight 4 3 . 0 4 . d 1.92. C r y s t a l l i n e b e r y l l i u m h y d r o x i d e i s v e r y s l i g h t l y s o l u b l e in w a t e r and in dilute a l k a l i . Both f o r m s a r e r e a d i l y s o l u b l e in hot c o n c e n t r a t e d s o d i u m h y d r o x i d e .

REFERENCES:

L . H a v e s t a d and R . F r i c k e , Z . a n o r g . a l l g . C h e m . 188, 357 (1930).

R . F r i c k e and B . W u l l h o r s t , Z . a n o r g . a l l g . C h e m . 2 0 5 , 127 (1932).

R . F r i c k e and G . F . Huttig, Hydroxyde und O x y d h y d r a t e [ H y d r o x i d e s and H y d r a t e d O x i d e s ] , L e i p z i g 1937, p . 12, a s w e l l a s t h e l i t e r a t u r e c i t e d t h e r e .

(9)

Sodiu m Beryllate s

I. C o n c e n t r a t e d s o d i u m h y d r o x i d e s a t u r a t e d with b e r y l l i u m h y d r o x i d e , o r a l c o h o l i c p o t a s s i u m h y d r o x i d e s a t u r a t e d w i t h p o t a s s i u m b e r y l l a t e , both p r e p a r e d with e x c l u s i o n of C 0², i s f i l t e r e d in t h e p r e s e n c e of KOH t h r o u g h an a s b e s t o s f i l t e r in a s i l v e r funnel. T h e f i l t r a t e i s v a c u u m - e v a p o r a t e d in a n i c k e l d i s h in t h e p r e s e n c e of H²S 0⁴ and KOH. T h e f i r s t p r e c i p i t a t e c o n s i s t s o f N a²C 0³a n d s o m e B e ( O H )². A s s o o n a s t h e s e p a r a t i o n of t h e s n o w - w h i t e , s h i n i n g s o d i u m b e r y l l a t e b e g i n s , t h e f i l t r a t i o n i s r e p e a t e d and t h e s o l u t i o n f u r t h e r e v a p o r a t e d . T h e p r o d u c t i s w a s h e d with a l c o h o l and d r i e d in a v a c u u m d e s i c c a t o r .

II. M o n o s o d i u m b e r y l l a t e and B e ( O H )² e x i s t a s t h e s o l i d - p h a s e c o m p o n e n t s in t h e s y s t e m B e O - N a O H - H²0 a t 30°C, when t h e c o n c e n t r a t i o n s of NaOH and BeOH a r e about 33% a n d 4 . 3 % , r e s p e c t i v e l y ; at h i g h e r s o d i u m h y d r o x i d e c o n c e n t r a t i o n s , m o n o s o d i u m b e r y l l a t e i s t h e only s o l i d - p h a s e c o m p o n e n t .

III. S o d i u m o r t h o b e r y l l a t e with t h e f o r m u l a N a⁴B e 0³ i s o b t a i n e d a s a white p o w d e r via t h e r e a c t i o n of N a²0 with BeO in a s i l v e r b o a t at 500°C. F o r t e c h n i q u e s of w o r k i n g with e x c l u s i o n of CCX, a n d a t m o s p h e r i c m o i s t u r e , s e e P a r t I, t h e s e c t i o n on o r t h o s t a n n a t e s and t h e o r i g i n a l l i t e r a t u r e .

PROPERTIES:

S t r o n g l y h y g r o s c o p i c c r y s t a l s , d e c o m p o s e d b y a t m o s p h e r i c

c o

²

.

REFERENCES:

I. G. K r u s s and H. M o r a h t , L i e b i g s Ann. C h e m . 260, 174 (1890).

II. R. F r i c k e , A. M u n c h m e y e r and F . E n g e l h a r d t , Z. a n o r g . a l l g . C h e m . 166, 247 (1927).

III. E . Z i n t l and W. M o r a w i e t z , Z . a n o r g . a l l g . C h e m . 2 3 6 , 372 (1938).

Berylliu m Sulfid e BeS

B e r y l l i u m sulfide m a y b e p r e p a r e d e i t h e r by (I) s y n t h e s i s f r o m t h e e l e m e n t s , (II) r e a c t i o n of t h e c h l o r i d e with Η²S (which, h o w e v e r , d o e s not y i e l d c h l o r i n e - f r e e m a t e r i a l ) , o r (ΠΙ) f r o m B e S 0⁴o r B e O .

T h e l a s t two m e t h o d s s h o u l d b e u s e d only when m e t a l l i c Be i s u n a v a i l a b l e .

I. Be + S = BeS

9.0 32.1 41.1

Sulfur v a p o r m i x e d with Η² i s p a s s e d o v e r p u r e Be at a t e m p e r a t u r e of about 1150°C. T h e g r o u n d g l a s s a p p a r a t u s , shown in F i g .

(10)

896 P . E H R L I C H

254, c o n s i s t s e s s e n t i a l l y of a q u a r t z t u b e with an e n l a r g e m e n t at o n e e n d to s e r v e a s a s u l f u r r e c e i v e r ; t h e Be i s c o n t a i n e d in a b o a t m a d e of q u a r t z o r , s t i l l b e t t e r , of A 1²0³ o r B e O , and p l a c e d at t h e c e n t e r of t h e q u a r t z t u b e . To o b t a i n a q u a n t i t a t i v e r e a c t i o n , t h e p r o d u c t of the f i r s t r u n i s finely p u l v e r i z e d in an a g a t e m o r t a r and

a g a i n r e a c t e d with t h e s u l f u r v a p o r .

F i g . 2 5 4 . P r e p a r a t i o n of b e r y l l i u m s u l f i d e .

Von W a r t e n b e r g s i m p l i f i e d t h e p r o c e s s a s f o l l o w s : a q u a r t z t u b e of 1 5 - m m . d i a m e t e r and 7 0 0 - m m . l e n g t h , s e a l e d a t t h e l o w e r e n d , i s c h a r g e d with 6 g. of Be and 30 g. of d i s t i l l e d S; t h e t u b e i s s l i p p e d into a p l a t i n u m - w o u n d f u r n a c e , which i s i n c l i n e d at a 45°

a n g l e ; t h e Be i s f i r s t g r o u n d in a coffee m i l l and s c r e e n e d to g i v e p a r t i c l e s 0 . 2 - 0 . 5 m m . in d i a m e t e r . T h e f u r n a c e i s h e a t e d to 1350°C for about two h o u r s ; t h e sulfur e v a p o r a t e s c o n s t a n t l y and flows b a c k down t h e p r o t r u d i n g p o r t i o n of the t u b e , w h i c h a c t s a s a r e f l u x c o n d e n s e r . T h e sulfur v a p o r t h u s e x c l u d e s a i r . After r e m o v a l a n d cooling of t h e t u b e , i t s l o w e r end i s cut off and t h e e a s i l y r e m o v e d , s i n t e r e d c a k e i s c r u s h e d and a g a i n t r e a t e d with s u l f u r in t h e s a m e fashion. The cut-off t u b e end m a y b e r e s e a l e d on a n e w t u b e s e c t i o n . After t h e c a k e i s f r e e d of sulfur u n d e r v a c u u m , it s t i l l c o n t a i n s Be f l a k e s , w h i c h , h o w e v e r , c a n b e s e p a r a t e d b y p u l v e r i z i n g and s c r e e n i n g ( 0 . 1 - m m . s c r e e n ) to s u c h a n e x t e n t t h a t t h e d i r t y y e l l o w p o w d e r , which s t i l l r e t a i n s a faint o d o r , no l o n g e r e v o l v e s H² when added t o d i l u t e a c i d s . A n a l y s i s s h o w s a BeS c o n t e n t of 98% on t h e b a s i s of t h e d e t e r m i n a t i o n of H²S evolved; h o w e v e r , 2.4% of t h e p r o d u c t i s i n s o l u b l e in d i l u t e H²S 0⁴.

II. BeCl² + H²S = BeS + 2 H C 1

79.9 34.1 41.1 72.9

B e r y l l i u m c h l o r i d e , o b t a i n e d by p a s s i n g HC1 o v e r a r e d - h o t m i x t u r e of BeO 4- C, i s p u r i f i e d a s t h o r o u g h l y a s p o s s i b l e by r e - p e a t e d s u b l i m a t i o n in a q u a r t z t u b e . Without o p e n i n g t h e a p p a r a t u s , t h e B e C l² i s r e a c t e d with p u r e H²S ( p r e p a r e d f r o m S and Hg). Too r a p i d s u b l i m a t i o n of t h e B e C l² (at about 400°C) m u s t b e a v o i d e d b y

(11)

i n c r e a s i n g t h e t e m p e r a t u r e only v e r y g r a d u a l l y if a s a t i s f a c t o r y y i e l d i s to b e o b t a i n e d . F u r t h e r m o r e , t h e r e a c t i o n m u s t b e l o c a l i z e d b y m e a n s of a w a t e r - c o o l e d q u a r t z t u b e , which i s i n s e r t e d in t h e q u a r t z r e a c t i o n t u b e . T h e c h l o r i d e s h o u l d b e s u b l i m e d in t h e H²S s t r e a m b a c k and f o r t h s e v e r a l t i m e s . T h e p r o d u c t , which s t i l l h a s a high c h l o r i n e c o n t e n t , i s h e a t e d at 850 to 950° in t h e H²S s t r e a m for an a d d i t i o n a l h o u r . T h i s y i e l d s a g r a y i s h , a m o r p h o u s sulfide which s t i l l c o n t a i n s t r a c e s of c h l o r i d e and which i s

l e s s s t a b l e in a i r t h a n t h e p r o d u c t m a d e by m e t h o d I.

III. O t h e r p r e p a r a t i v e m e t h o d s a r e t h e d r y r e d u c t i o n of B e S 0⁴ with a g e n t s c o n t a i n i n g no h y d r o g e n , e . g . , S v a p o r , CO, C a C², Zn o r Al, T h e b e s t y i e l d s a r e o b t a i n e d with Al (97%, b a s e d on B e S 0⁴) . T h e r e d u c t i o n b e g i n s a t 560°C.

B e r y l l i u m sulfide m a y a l s o b e o b t a i n e d by r e a c t i o n of CSg with BeO at t e m p e r a t u r e s a b o v e 1200°C.

PROPERTIES:

G r a y t o w h i t e p o w d e r w i t h a faint o d o r of H³S w h e n e x p o s e d to a i r . C r y s t a l l i z e s in s t r u c t u r e t y p e B3 (ZnS). d 2 . 3 6 .

REFERENCES:

I· H. von W a r t e n b e r g , Z . a n o r g . a l l g . C h e m . 2 5 2 , 136 (1943).

II. E . T i e d e and F . G o l d s c h m i d t , B e r . d t s c h . c h e m . G e s . 6 2 , 758 (1929).

ΠΙ. P . S i l b e r , Ann. C h i m . (12) 7, 182 (1952).

Berylliu m Selenid e an d Berylliu m Tellurid e BeSe, BeTe

BeSe

Be + Se = BeSe

9.0 79.0 88.0

B e r y l l i u m s e l e n i d e i s p r e p a r e d f r o m t h e e l e m e n t s in a H² s t r e a m at 1100°C. P u r e Se and p u r e p u l v e r i z e d Be a r e p l a c e d in a q u a r t z r e a c t i o n t u b e in s e p a r a t e b o a t s m a d e of A 1²0 o r B e O , (or at l e a s t of q u a r t z ) . T h e h y d r o g e n s h o u l d p a s s f i r s t o v e r t h e h e a t e d Se and t h e n , when l a d e n with i t s v a p o r , o v e r t h e B e . A w a s h b o t t l e filled with l e a d a c e t a t e i s m o u n t e d at t h e exit end of t h e r e a c t i o n t u b e to a b s o r b t h e v e r y t o x i c H²S e p r e s e n t in t h e d i s c h a r g e d g a s . The Se i s h e a t e d with a B u n s e n b u r n e r ; t h e u n i f o r m h e a t of an e l e c t r i c f u r n a c e i s r e q u i r e d for t h e B e . T h e BeSe s o o b t a i n e d often s h o w s a t e n d e n c y to c r y s t a l l i z e in long n e e d l e s .

(12)

8 9 8 P . E H R L I C H

BeTe

B e r y l l i u m t e l l u r i d e c a n b e p r e p a r e d f r o m t h e e l e m e n t s b y t h e s a m e m e t h o d .

Be + Te = BeTe

9.0 127.6 136.6

PROPERTIES:

G r a y p o w d e r s , d e c o m p o s i n g r e l a t i v e l y r a p i d l y in a i r . C r y s t a l l i z e in s t r u c t u r e t y p e B3 (ZnS t y p e ) , d (BeSe) 4 . 3 2 , d (BeTe) 5.09.

REFERENCE:

P r i v a t e c o m m u n i c a t i o n f r o m E . T i e d e .

Berylliu m Nitrid e Be³N²

3 Be + 2 N H³ = Be³N² + 3 H²

27.1 34.1 55.1 6.1

I n s t e a d of s y n t h e s i z i n g t h e n i t r i d e f r o m t h e e l e m e n t s , it m a y b e o b t a i n e d m o r e e a s i l y and in h i g h e r y i e l d b y h e a t i n g m e t a l l i c Be in an N H³ s t r e a m .

T h e c o m m e r c i a l m e t a l i s c r u s h e d in a s t e e l m o r t a r and s c r e e n e d t h r o u g h a 1 0 0 - m e s h (per inch) s i e v e ; t h e p o w d e r i s p l a c e d in a c o r u n d u m b o a t , which i s h e a t e d in a p o r c e l a i n t u b e in a d r y N H³ s t r e a m at 850°C for t h r e e h o u r s . T h e r e a c t i o n p r o d u c t i s t h e n p u l v e r i z e d in an a g a t e m o r t a r and h e a t e d in t h e N H³ s t r e a m a t 1000°C; t h i s p r o c e d u r e i s r e p e a t e d t h r e e t i m e s . The p r o d u c t s o o b t a i n e d u s u a l l y c o n t a i n s only 9 4 - 9 5 % B e³N². A p u r e r p r o d u c t m i g h t be o b t a i n e d b y t h e u s e of m e t a l d i s t i l l e d in high v a c u u m and b y c a r e f u l m a n i p u l a t i o n .

PROPERTIES:

G r a y - w h i t e p o w d e r ; s t a b l e in a i r ; d e c o m p o s e s r a t h e r s l o w l y on c o n t a c t with boiling a c i d s . C r y s t a l l i z e s in s t r u c t u r e t y p e D 5³

(C s e s q u i o x i d e t y p e ) .

REFERENCES:

F . F i c h t e r and E . B r u n n e r , Z . a n o r g . a l l g . C h e m . 9 3 , 86 (1915).

J . R i e b e r , T h e s i s , H a n n o v e r , 1930.

M. von S t a c k e l b e r g a n d R . P a u l u s , Z . p h y s . C h e m . (B) 2 2 , 305 (1933).

(13)

Berylliu m Azid e Be(N³)²

Be(CH³)² + 2 H N³ Be(N^s)² + 2 C H⁴

39.0 86.0 93.0 44.81

P u r e d i m e t h y l b e r y l l i u m i s s u b l i m e d into a r e a c t i o n v e s s e l c o o l e d with liquid N²; t h e n an a b s o l u t e l y d r y e t h e r s o l u t i o n of e x c e s s H N³ i s c o n d e n s e d on top of t h e d i m e t h y l b e r y l l i u m l a y e r . A s t h e r e a c t i o n m i x t u r e t h a w s , a v i g o r o u s r e a c t i o n with e v o l u t i o n of m e t h a n e s t a r t s e v e n b e f o r e all of t h e e t h e r i s m e l t e d ( m . p .

—116°C), and B e ( N³)² s e p a r a t e s out a s a white p r e c i p i t a t e . T h e e t h e r a n d e x c e s s H N³ a r e t h e n d i s t i l l e d off u n d e r high v a c u u m .

PROPERTIES:

W h i t e , s o l i d s u b s t a n c e ; e x p l o s i v e in t h e p r e s e n c e of a f l a m e ; i n - s e n s i t i v e to s h o c k . R a p i d l y d e c o m p o s e d in m o i s t a i r . H y d r o l y z e s in a q u e o u s s o l u t i o n to s u c h an e x t e n t t h a t t h e s u b s t a n c e m a y not b e r e c o v e r e d u n d e c o m p o s e d e v e n when t h e s o l v e n t i s v e r y c a r e f u l l y d i s t i l l e d off in a high v a c u u m .

REFERENCE:

E . W i b e r g and H. M i c h a u d , Z . N a t u r f o r s c h . 9_b, 502 (1954).

A m i x t u r e of m e t a l l i c B e ( t u r n i n g s o r p o w d e r ) and finely divided g r a p h i t e o r c a l c i n e d a c e t y l e n e b l a c k i s r e a c t e d at 1700° for 20 t o 30 m i n u t e s . T h e y i e l d i s 85%.

Berylliu m Carbide s Be²C; BeC²

Be²C

2 Be + C = Be²C

18.0 12.0 30.1

II. 2 BeO + 2 C = Be²C + 2 CO

50.0 36,0 30.0 56.0

A b l e n d of c a l c i n e d BeO and half i t s weight of c a r b o n m a d e f r o m s u g a r i s m i x e d with 5% of s t a r c h and 15% of w a t e r , c o m p r e s s e d into c y l i n d e r s , d r i e d , c a l c i n e d , and finally h e a t e d in H² a t two

(14)

9 0 0 P . E H R L I C H

a t m o s p h e r e s g a u g e and 1930°C for 10 to 15 m i n u t e s ; an 85-92%

p u r e p r o d u c t i s o b t a i n e d a s beautiful, b r i c k - r e d c r y s t a l s . T h e r e a c t i o n d o e s not s t a r t b e l o w 1700°C, but t h e c a r b i d e d e c o m p o s e s e x t e n s i v e l y above 2200°C. F o r t h i s r e a s o n , t h e m o r e c o n v e n i e n t e l e c t r i c a r c f u r n a c e p r o c e s s i s not r e c o m m e n d e d . A c c o r d i n g to M e s s e r k n e c h t and B i l t z , t h e s i m p l e s t f o r m of t h e a r c p r o c e s s a p p a r a t u s c o n s i s t s of a g r a p h i t e c r u c i b l e w i t h a c a r b o n e l e c t r o d e i m m e r s e d in t h e r e a c t a n t m i x t u r e (110v., 30 a m p . ) .

L o w c o n c e n t r a t i o n p r o d u c t s m a y b e e n r i c h e d by t r e a t m e n t with hot d i l u t e h y d r o c h l o r i c a c i d (however, a p o r t i o n of t h e c a r b i d e i s l o s t by d e c o m p o s i t i o n ) . T h e e x c e s s C m a y t h u s b e d e c a n t e d and t h e BeO d i s s o l v e d . In t h i s m a n n e r , an e n r i c h m e n t to m o r e t h a n 95%

B e²C i s p o s s i b l e ; t h e b a l a n c e i s BeO and f r e e C.

PROPERTIES:

Y e l l o w - r e d , finely c r y s t a l l i n e p o w d e r , s l o w l y d e c o m p o s i n g in m o i s t a i r . C r y s t a l l i z e s in s t r u c t u r e type C I (antifluorite t y p e ) .

REFERENCES:

I. G. O e s t e r h e l d , Z . a n o r g . C h e m . 9 7 , 1 (1916); M. W. M a l l e t t , E . A. D u r b i n , M. C. Udy, D. A. Vaughan and E . A. C e n t e r , J . E l e c t r o c h e m . Soc. 1 0 1 , 298 (1954).

II. F . F i c h t e r and E . B r u n n e r , Z. a n o r g . C h e m . 9 3 , 91 (1915); J . K i e l l a n d and L . T r o n s t a d , Kong. N o r s k e Vidensk. S e l s k . F o r h a n d l . 8, 147 (1936); P . L e b e a u , C o m p t e s R e n d u s H e b d . S e a n c e s A c a d . Sci. 1 2 1 , 496 (1895); C. M e s s e r s k n e c h t and W. B i l t z , Z . a n o r g . a l l g . C h e m . 148, 153 (1925); M. von S t a k k e l b e r g and F . Q u a t r a m , Z . p h y s . C h e m . ( B ) 2 7 , 50 (1934).

BeC²

Be + C²H² = B e C² + H² 9.0 26.0 33,0 2.0

A c c o r d i n g to D u r a n d , B e C² i s f o r m e d b y p a s s i n g d r y a c e t y l e n e at 450°C o v e r Be p o w d e r in a P y r e x t u b e . T h e p r o d u c t a p p e a r s b l a c k due to f r e e C f o r m e d via t h e r m a l d e c o m p o s i t i o n of t h e a c e t y l e n e .

PROPERTIES:

G e n e r a t e s a c e t y l e n e with HgO and ( m o d e r a t e l y ) with d i l u t e HC1.

REFERENCE:

J . F . D u r a n d , Bull. Soc. C h i m . F r a n c e [4] 3 5 , 1141 (1924).

(15)

Berylliu m Acetat e Be(CH³COO)²

B e40 ( C H3C O O )6 + 2 C H3C O · CI + 2 C H3C O O H 406,3 157.0 120,1

= 4 B e ( C H3C O O )2 + 2 HCl + ( C H3C O )20 508,4 72,9 102.1

B a s i c b e r y l l i u m a c e t a t e (4 g.) i s d i s s o l v e d in 50 m l . of b o i l i n g g l a c i a l a c e t i c a c i d and r e f l u x e d with 4 - 5 g. of a c e t y l c h l o r i d e for a s h o r t t i m e . T h e p r e c i p i t a t e of B e ( C H³C O O )² f o r m i n g a f t e r a few m i n u t e s i s f i l t e r e d off, w a s h e d with g l a c i a l a c e t i c a c i d a n d with c o l d c h l o r o f o r m , and d r i e d in a v a c u u m d e s i c c a t o r . T h e y i e l d i s 9 0 - 9 4 % .

PROPERTIES:

Stable for s e v e r a l w e e k s in a c l o s e d v e s s e l at r o o m t e m p e r a - t u r e . Slowly s p l i t s off a c e t i c a n h y d r i d e ( r a p i d l y when h e a t e d ) and i s c o n v e r t e d to b a s i c b e r y l l i u m a c e t a t e , which s u b l i m e s . U n d e r - g o e s p a r t i a l d e c o m p o s i t i o n to a c e t i c a n h y d r i d e and b e r y l l i u m o x i d e when h e a t e d r a p i d l y .

B a r e l y a t t a c k e d by c o l d w a t e r , i s h y d r a t e d at e l e v a t e d t e m p e r a - t u r e . I n s o l u b l e in a l l s o l v e n t s for b a s i c b e r y l l i u m a c e t a t e .

REFERENCE:

J . B e s s o n and H. D. H a r d t , Z. a n o r g . a l l g . C h e m . 2 7 7 , 188 (1954).

Basi c Berylliu m Acetat e Be⁴0(CH³COO)^e

I. B a s i c b e r y l l i u m c a r b o n a t e (40 g.) i s m i x e d with 80 m l . of g l a c i a l a c e t i c a c i d and s t i r r e d , with h e a t i n g , until C 0² evolution c e a s e s . T h e end of t h e r e a c t i o n i s a l s o r e c o g n i z e d b y t h e s t a r t of p r e - c i p i t a t i o n of w h i t e , s e m i t r a n s l u c e n t c r y s t a l s ; o t h e r w i s e , t h e r e i s a n a m o r p h o u s , white r e s i d u e . T h e s o l u t i o n i s c o o l e d t o r o o m t e m p e r a t u r e and t h e c r y s t a l l i z e d b a s i c a c e t a t e i s f i l t e r e d off a n d d r i e d in a i r .

T h e c r u d e p r o d u c t i s t r e a t e d with 6 0 - 8 0 m l . of c h l o r o f o r m , and a n y i n s o l u b l e r e s i d u e i s r e m o v e d by f i l t r a t i o n . T h e b a s i c s a l t , w h i c h c r y s t a l l i z e s in c o l o r l e s s o c t a h e d r a , i s f i l t e r e d off and f r e e d of r e s i d u a l c h l o r o f o r m in a v a c u u m d e s i c c a t o r . T h e p r o d u c t m e l t s a t 284°C a n d s u b l i m e s without a r e s i d u e at r e d u c e d p r e s s u r e . T h e y i e l d i s 28 g .

(16)

9 0 2 P. E H R L I C H

II. A m e t h o d d e s c r i b e d by H a r d t a v o i d s c o n t a m i n a t i o n of t h e p r o d  u c t by a m m o n i u m s a l t s and s o l v e n t o c c l u s i o n s and m a k e s p u r i f i c a t i o n by s u b l i m a t i o n u n n e c e s s a r y .

B e r y l l i u m h y d r o x i d e o r b a s i c b e r y l l i u m c a r b o n a t e i s s t i r r e d with g l a c i a l a c e t i c a c i d to a p a s t e and e v a p o r a t e d to d r y n e s s in a l a b o r a t o r y oven at 120 to 130°C. T h e c r u d e p r o d u c t t h u s f o r m e d i s e x t r a c t e d with g l a c i a l a c e t i c a c i d in a Soxhlet a p p a r a t u s (using a g l a s s wool f i l t e r ) ; a f t e r c o o l i n g , it c r y s t a l l i z e s f r o m t h e e x t r a c t in w e l l - f o r m e d o c t a h e d r a , which a r e f i l t e r e d off and d r i e d a t 130°C.

T h i s i s followed b y a s e c o n d Soxhlet e x t r a c t i o n with C C 14, s i n c e t h e a m m o n i u m s a l t s f r o m t h e s t a r t i n g m a t e r i a l s t i l l r e m a i n u n d i s s o l v e d . T h e p r o d u c t i s a n a l y t i c a l l y p u r e a f t e r d r y i n g a t 100°C.

PROPERTIES:

At r o o m t e m p e r a t u r e t h e m o l e c u l a r l a t t i c e i s of t h e s p a c e g r o u p

Tn⁴ ( ° 0 · T r a n s i t i o n to o t h e r m o d i f i c a t i o n s ( γ , β) occurs a t 150 to 155°C. V e r y s o l u b l e in c h l o r o f o r m ; r e a d i l y s o l u b l e in b o i l i n g b e n z e n e , t o l u e n e , x y l e n e , T e t r a l i n and g l a c i a l a c e t i c a c i d ; l e s s s o l u b l e in C C 14, a c e t i c a n h y d r i d e and a c e t y l c h l o r i d e ; s p a r i n g l y s o l u b l e (0.3%) in d i e t h y l e t h e r .

In a n h y d r o u s b o i l i n g m e t h a n o l following i n i t i a l d i s s o l u t i o n , s p l i t s off a c e t i c a n h y d r i d e with f o r m a t i o n of h i g h l y a g g r e g a t e d b a s i c a c e t a t e s .

Quite s t a b l e in c o l d w a t e r , but i s r a p i d l y h y d r o l y z e d in hot w a t e r .

B e g i n s to s u b l i m e at about 200°C, s o f t e n s at about 280°C to a n e m a t i c o r s m e c t i c (liquid c r y s t a l ) s t a t e and m e l t s a t 183 to 184°C with s u b l i m a t i o n . May b e d i s t i l l e d at 1-2 a t m o s p h e r e s g a u g e . P u r e b a s i c b e r y l l i u m a c e t a t e l e a v e s a r e s i d u e of 0 . 3 - 0 . 5 % BeO a f t e r s u b l i m a t i o n .

F o r t h e p r e p a r a t i o n of b a s i c b e r y l l i u m f o r m a t e and b a s i c b e r y l l i u m p r o p i o n a t e , s e e t h e l i t e r a t u r e c i t e d u n d e r Π; a l s o H.

H e n d u s and H. D. H a r d t , Z . a n o r g . a l l g . C h e m . 2 7 7 , 127 (1954).

REFERENCES:

F . H a b e r and G. van O o r d t , Z. a n o r g . a l l g . C h e m . 4 0 , 465 (1904).

A. Stock, P . P r a e t o r i u s and O. P r i e s s , B e r . d t s c h . c h e m . G e s . 5 8 , 1571 (1925). U b u n g s b e i s p i e l e a u s d e r a n o r g . E x p e r i m e n t a l - c h e m i e [ P r a c t i c a l E x p e r i m e n t s in I n o r g a n i c C h e m i s t r y ] , L e i p z i g

1920, p . 2 1 2 .

I. T . M o e l l e r , A . J . Cohen and E . M a r v e l l in: L . F . A u d r i e t h , I n o r g a n i c S y n t h e s e s , Vol. Ill, New Y o r k - T o r o n t o - L o n d o n 1950, p . 9.

p . 9.

II. J . B e s s o n and H. D. H a r d t , Z . a n o r g . a l l g . C h e m . 2 7 7 , 188 (1954); H. H e n d u s and H. D. H a r d t , Z. a n o r g . a l l g . C h e m . 2 8 6 , 265 (1956); H. D. H a r d t , Z . a n o r g . a l l g . C h e m . 2 8 6 , 254 (1956).

(17)

Magnesiu m

M g

G e n e r a l l y , v e r y p u r e m a g n e s i u m i s p r e p a r e d by r e f i n i n g c o m - m e r c i a l m a g n e s i u m via d i s t i l l a t i o n o r , s t i l l b e t t e r , by s u b l i m a t i o n in high v a c u u m .

M a g n e s i u m i s u s u a l l y m a d e c o m m e r c i a l l y by e l e c t r o l y s i s of m o l t e n , d e h y d r a t e d c a r n a l l i t e ( M g C l² · KC1), with an A c h e s o n g r a p h i t e a n o d e and an i r o n c a t h o d e .

T h e c r u d e m e t a l o b t a i n e d by e l e c t r o l y s i s c o n t a i n s up to 2.7% CI, b e s i d e s o t h e r i m p u r i t i e s ( F e , A l , Si, N). P u r i f i c a t i o n is effected by m e l t i n g with fluxing a g e n t s o r , b e t t e r , by r e p e a t e d f i l t r a t i o n . T h i s m a y be done s i m p l y by p u s h i n g a s h e e t i r o n s c r e e n d o w n w a r d t h r o u g h t h e m e l t . T h i s r e d u c e s t h e c h l o r i n e c o n t e n t c o n s i d e r a b l y (final c o n t e n t : 0.003% CI).

A n o t h e r m e t h o d of p u r i f i c a t i o n c o n s i s t s in r e f i n i n g with Z r . Addition of 2-4% of Z r C l⁴ to Mg m e l t s r e s u l t s in p r e c i p i t a t i o n of F e , A l , Si and Mn but not of Cu. The Z r c a n b e r e m o v e d by s u b - s e q u e n t p a s s a g e of H², s t i l l r e t a i n i n g t h e d e g r e e of p u r i t y p r e v i o u s l y a c h i e v e d . M a g n e s i u m t h u s p r e p a r e d i s h i g h l y r e s i s t a n t to c o r - r o s i o n .

P u r e m a g n e s i u m (99.9%), a b s o l u t e l y f r e e of h a l o g e n , i s o b - t a i n e d by t h e R a d e n t h e i n e r p r o c e s s .

I. SUBLIMATION OF THE CRUDE METAL

In t h e l a b o r a t o r y , t h e following s i m p l i f i e d m e t h o d m a y b e u s e d : t h e s u b l i m a t i o n v e s s e l shown in F i g . 255 (see a l s o the a p p a r a t u s d e s c r i b e d for t h e d i s t i l l a t i o n of Ca) c o n s i s t s of an i r o n t u b e ( 6 0 - m m . d i a m e t e r and 500 m m . long), which i s c l o s e d at one end and h a s a t h r e a d e d v a c u u m - t i g h t lid on t h e o t h e r . The lid is fitted with a n i p p l e for c o n n e c t i o n to a h i g h - v a c u u m s y s t e m . T h e l o w e r end of t h i s r e t o r t c o n t a i n s an i r o n t u b e / w i t h t h e c r u d e m a g n e s i u m ; t h e open end of t h e t u b e i s p r e f e r a b l y c l o s e d b y one o r two f i n e - m e s h w i r e s c r e e n s which a r e c l a m p e d to t h e t u b e . The c o n i c a l i r o n t u b e e is i n s e r t e d into t h e c o l d e r z o n e of t h e s u b l i m a t i o n v e s s e l . T h e t u b e c o n s i s t s of two h a l v e s h e l d t o g e t h e r by r i n g s (see F i g . 255). B e f o r e t h e p r e p a r a t i o n , t h e i n t e r i o r w a l l s of t h e t u b e a r e d u s t e d with MgO in o r d e r to p r e v e n t s t i c k i n g of t h e c o n d e n s a t e .

T h e s u b l i m a t i o n t e m p e r a t u r e i s s t a t e d in t h e l i t e r a t u r e to b e about 600°C at a v a c u u m of 10 ""³ m m . If t h e c o n d e n s i n g s u r f a c e i s at 400 to 500°C, t h e c r y s t a l s will b e d e n d r i t i c ; l a r g e r q u a n t i t i e s a g g l o m e r a t e to m a s s i v e b l o c k s . At h i g h e r t e m p e r a t u r e s (600°C), l a r g e s i n g l e c r y s t a l s a r e f o r m e d .

(18)

9 0 4 P . E H R L I C H

T h e m e t a l o b t a i n e d a f t e r a s i n g l e s u b l i m a t i o n c o n t a i n s F e , A l , Si and CI in a m o u n t s l e s s t h a n 0.001%. After r e p e a t e d s u b l i m a t i o n t h e i m p u r i t i e s c a n n o t be identified e i t h e r c h e m i c a l l y o r s p e c t r o - s c o p i c a l l y . T h e s u b l i m e d m e t a l c a n be r e m e l t e d in an a r g o n a t m o s p h e r e at 3 0 0 - 4 0 0 m m .

an

furnace

II

v a c u u m

F i g . 2 5 5 . P u r i f i c a t i o n of m a g n e s i u m b y s u b l i m a t i o n .

II. When l a r g e r q u a n t i t i e s (about 1 kg.) m u s t b e s u b l i m e d in a s i n g l e o p e r a t i o n , the m e t a l i s c o n d e n s e d in an a p p a r a t u s of l a r g e r c a p a c i t y , u s i n g a w a t e r - c o o l e d c y l i n d e r .

PROPERTIES:

A t o m i c weight 2 4 . 3 2 . M . p . 650°C, b . p . 1102°C; d 1.737. C r y s t a l l i z e s in s t r u c t u r e t y p e A 3 .

Cold w a t e r r e a c t s only s l o w l y with m a g n e s i u m ; t h e r e a c t i o n i s m u c h m o r e r a p i d in b o i l i n g w a t e r . T h e m e t a l d i s s o l v e s v i o l e n t l y in a c i d s .

REFERENCES:

G m e l i n , Handb. d. a n o r g a n . C h e m i e , 8 t h e d . , Vol. 27B ( M a g n e s i u m ) , p . 1 2 1 .

Η· F u n k , Die D a r s t e l l u n g d e r M e t a l l e i m L a b o r a t o r i u m [ P r e p a r a tion of M e t a l s in the L a b o r a t o r y ] S t u t t g a r t 1938, p . 2 6 . Κ. E . Mann, Z . M e t a l l k u n d e 4 4 , 264 (1953).

I. W. Kaufmann and P . S i e d l e r , Z. E l e k t r o c h e m . 37^ 492 (1931).

Π. I. H e r e n g u e l and G. C h a u d r o n , C o m p t e s R e n d u s Hebd. S e a n c e s A c a d . Sci. 193, 771 (1931); 195, 1272 (1932); s e e a l s o G.

C h a u d r o n in A. E . van A r k e l , R e i n e M e t a l l e [ P u r e M e t a l s ] , B e r l i n 1939, p . 1 1 1 .

(19)

Magnesiu m Hydrid e

M g H2

I. Mg + H² = MgH²

24.3 22.41 26.3

M a g n e s i u m and h y d r o g e n r e a c t a t 570°C and 200 a t m o s p h e r e s in t h e p r e s e n c e of M g l² a s a h y d r o g e n t r a n s f e r a g e n t to f o r m M g H². T h e y i e l d i s 60%.

II. M a g n e s i u m h y d r i d e i s f o r m e d when m a g n e s i u m d i a l k y l s (diethyl, d i b u t y l , diphenyl) o r t h e c o r r e s p o n d i n g G r i g n a r d c o m p o u n d s a r e h e a t e d to 175-200°C u n d e r high v a c u u m for s e v e r a l h o u r s .

PROPERTIES:

White, w a t e r - s e n s i t i v e s o l i d ; not s p o n t a n e o u s l y c o m b u s t i b l e . I n s o l u b l e in e t h e r ; n o n v o l a t i l e ; s t a b l e to 280°C u n d e r v a c u u m .

REFERENCES:

I. E , W i b e r g , H. G o e l t z e r and R. B a u e r , Z . N a t u r f o r s c h . 6 b , 394 (1951); s e e a l s o F . E l l i n g e r et a l . J . A m e r . C h e m . S o c 77, 2647 (1955).

II. E . W i b e r g and R. B a u e r , Z . N a t u r f o r s c h . 5_b, 396 (1950); E . W i b e r g and R. B a u e r , C h e m . B e r . 8 5 , 593 (1952).

Magnesiu m Chlorid e

M g C l²

ANHYDROUS M g C l2

In t h e m e t h o d d e v e l o p e d by R i c h a r d s , M g C l²i s p r e p a r e d f r o m a m i x t u r e of N H⁴C 1 4- MgCl · 6 H²0 o r f r o m t h e double s a l t N H⁴C 1 · M g C l². 6 H²0 by d e h y d r a t i o n in a HC1 s t r e a m . T h e r e a c t i o n of MgO with a g a s m i x t u r e of CO and C l² i s m u c h b e t t e r s u i t e d for t h e p r e p a r a t i o n of l a r g e r q u a n t i t i e s ( m o r e t h a n 100 g . ) .

I e NH⁴C1 + MgCl² · 6 H²0 or

53-5 203.3

NH4CI · MgCl² · 6 H²0 = MgCl² + NH4CI f 6 H²0

256.8 95.2 53.5 108.1

E q u i m o l a r q u a n t i t i e s of M g C l²- 6 H²0 a n d N H⁴C 1 a r e c r y s t a l - l i z e d f r o m a q u e o u s s o l u t i o n s o m e w h a t a b o v e 50°C. After s e p a r a t i n g

(20)

906 P . EHRL1CH

t h e m o t h e r l i q u o r at t h i s t e m p e r a t u r e t h e s a l t i s r e c r y s t a l l i z e d o n c e , s l i g h t l y p r e d r i e d and filled while s t i l l hot into a q u a r t z b o a t , which i s t h e n i n s e r t e d into a q u a r t z t u b e . D e h y d r a t i o n in a d r y HC1 s t r e a m p r o c e e d s f i r s t at 100°C for t h r e e h o u r s (avoid m e l t i n g of t h e h y d r a t e d c r y s t a l s ) , t h e n at 250°C for one h o u r , and finally at 400°C for one h o u r . F i n a l l y , t h e p r o d u c t i s q u i c k l y m e l t e d and f r e e d of HC1 while cooling in a s t r e a m of C 0². T h e s a l t t h u s p r e p a r e d c o n t a i n s about 0 . 1 % MgO and 0.05% S i 0²; it m a y b e s t o r e d o v e r P²0⁵.

If high p u r i t y i s not r e q u i r e d , it will suffice to s t a r t with a m i x t u r e of N H⁴C 1 and M g C l²- 6 H²0 .

T h e c o n s u m p t i o n of HC1 m a y b e r e d u c e d s u b s t a n t i a l l y t h r o u g h d e h y d r a t i o n of t h e h e x a h y d r a t e o r of a m m o n i u m c a r n a l l i t e by h e a t i n g at 200°C u n d e r v a c u u m o r by s t o r a g e in a d e s i c c a t o r o v e r P²0⁵. The d r y i n g with HC1 m a y t h e n b e s t a r t e d d i r e c t l y at 200°C.

E v e n though HC1 b e g i n s to s p l i t off at 106°C when t h e h e x a h y d r a t e i s h e a t e d in a i r , it i s p o s s i b l e to d r y t h e m a t e r i a l at 150°C without f o r m a t i o n of u n d e s i r a b l e a m o u n t s of b a s i c s a l t , p r o v i d e d the e v a p o r a t i o n i s r a p i d . It i s a d v i s a b l e to p l a c e the h e x a h y d r a t e in a l a r g e p o r c e l a i n d i s h c o v e r e d with a wide funnel, which s e r v e s a s a p a r t i a l c o n d e n s e r of t h e h y d r o c h l o r i c a c i d v a p o r s f o r m e d . T h u s , t h e f o r m a t i o n of t h e b a s i c s a l t i s r e d u c e d to a m i n i m u m . T h e d i h y d r a t e b e g i n s to c r y s t a l l i z e at 180°C. At t h i s p o i n t t h e m e l t i s p o u r e d onto an a l u m i n u m s h e e t and c r u s h e d while s t i l l w a r m . T h i s p r o d u c t s t i l l c o n t a i n s 2 . 3 - 2 . 8 m o l e s of w a t e r p e r m o l e of M g C l².

A c c o r d i n g to T r e a d w e l l , t h e HC1 m a y b e r e c y c l e d a f t e r d r y i n g with c o n c e n t r a t e d H g S O ^ but t h i s r e q u i r e s e l a b o r a t e e q u i p m e n t ; b e s i d e s , t r a c e s of c h l o r o s u l f o n i c a c i d f o r m e d r e a c t with M g C l² to y i e l d M g S 0⁴.

Π. MgO + Cl² + CO = M g C l² + CO,

40.3 70.9 28.0 95.2 44.0

M a g n e s i u m oxide c a n b e c h l o r i n a t e d q u a n t i t a t i v e l y only in t h e p r e s e n c e of a r e d u c i n g a g e n t (CO). T h e r e a c t i o n d e p e n d s c r i t i c a l l y on t h e t h e r m a l p r e t r e a t m e n t of t h e MgO; m a g n e s i u m c a r b o n a t e c a l c i n e d at 800°C is s t i l l v e r y r e a c t i v e . C o m m e r c i a l CO in c y l i n d e r s i s not s u i t a b l e , s i n c e t h e Η² it c o n t a i n s f o r m s w a t e r , which d a m a g e s t h e a p p a r a t u s ; for t h i s a p p l i c a t i o n CO i s p r e p a r e d in a s m a l l g e n e r a t o r .

a. Carbon monoxide generator. T h e r e a c t o r i s a v e r  t i c a l l y m o u n t e d q u a r t z tube with an I.D. of 20 m m . and length of 600 m m . , which i s m a i n t a i n e d at about 950°C. A s o m e w h a t n a r r o w e r , s e a l e d - o f f q u a r t z t u b e is p u s h e d into t h e l o w e r hot z o n e ; t h i s t u b e s e r v e s a s a r e t a i n i n g g r a t i n g . T h e r e a c t o r i s c h a r g e d

(21)

with d r y a c t i v a t e d c a r b o n of 5 - m m . p a r t i c l e s i z e and m a y b e r e f i l l e d t h r o u g h a s i d e a r m s e a l e d on at t h e u p p e r end. To s t a r t t h e r e a c t i o n , CQs f r o m a c y l i n d e r i s a d d e d f r o m t h e t o p . A s m a l l CO f l a m e i s allowed to b u r n at a c a p i l l a r y b r a n c h i n g off f r o m t h e o u t l e t tube to p r o v i d e a s i m p l e t e s t for t h e CO c o n t e n t of t h e g e n e r a t e d g a s . T h e o u t l e t g a s p a s s e s t h r o u g h a p r e s s u r e r e l i e f v a l v e and a bubble c o u n t e r and i s t h e n m i x e d with C l², which i s m e t e r e d by t h e s a m e m e t h o d .

b. Magnesium oxide furnace. The r e a c t i o n v e s s e l i s a v e r t i c a l l y m o u n t e d , 7 0 0 - m m . - l o n g q u a r t z tube with an I. D . of 35 m m . In the l o w e r p o r t i o n t h e r e i s a 4 - m m . - d i a m e t e r , f u n n e l - s h a p e d , c e n t e r e d d r i p n o z z l e filled with a l a y e r of q u a r t z f r a g m e n t s to s u p p o r t a c h a r g e of 500 g. of MgO. T h e g a s flow r a t e i s 400 m l . / m i n . (200 m l . C l² 4- 200 m l . CO), and t h e r e a c t i o n t e m p e r a t u r e i s 750°C. T h e exit g a s h a s a 1% e x c e s s of CO and t h i s e n s u r e s t h a t t h e C l² c o n t e n t i s k e p t b e l o w 3 · 1 0 "⁵% . T h e g a s e s flow u p w a r d , c o u n t e r c u r r e n t to t h e s a l t , w h i c h d r i p s down. T h e s a l t d r o p s e m e r g i n g f r o m the n o z z l e s h o u l d fall f r e e into t h e r e c e i v e r w h i c h i s m o u n t e d u n d e r n e a t h by m e a n s of a g r o u n d g l a s s joint. T h e p u r e w h i t e , b r i t t l e r o d s and g r a i n s of M g C l² m a y b e e a s i l y r e m o v e d l a t e r . H o w e v e r , t h e e n t i r e oxide c h a r g e m u s t b e w e t t e d with m o l t e n c h l o r i d e b e f o r e t h e f i r s t d r o p s a p p e a r . T h i s o c c u r s only 2 - 3 h o u r s a f t e r t h e s t a r t of t h e c h l o r i n a t i o n .

T h e exit g a s e s f r o m t h e top of t h e r e a c t o r p a s s a s m a l l d u s t c o l l e c t o r , which r e t a i n s , a s i d e f r o m t h e d u s t , t h e i m p u r i t i e s of t h e o x i d e . T h e g a s e s a r e t h e n v e n t e d . T h r o u g h a c a p i l l a r y b r a n c h i n g off t h e g a s d i s c h a r g e l i n e , a s m a l l g a s s t r e a m m a y be d i v e r t e d to a B u n s e n f l a m e c o n t a i n i n g a glowing c o p p e r w i r e . In t h i s way o n e m a y t e s t t h e g a s c o m p o s i t i o n . T h e d e s i r e d e x c e s s of CO c a n b e r e c o g n i z e d by a faintly b l u e c a s t ; t r a c e s of CI g i v e a g r e e n c o p p e r f l a m e ( B e i l s t e i n t e s t ) .

PROPERTIES:

L e a f y c r y s t a l l i n e m a s s . M e l t s at 7 1 2 ° C t o a w a t e r - c l e a r , m o b i l e liquid. May be d i s t i l l e d at b r i g h t r e d h e a t in a H² s t r e a m , d 2 . 4 1 . M o r e h y g r o s c o p i c t h a n t h e c h l o r i d e s of t h e h i g h e r a l k a l i n e e a r t h m e t a l s . L i b e r a t e s C l² when h e a t e d to 300°C f o r m i n g o x i d e s and o x y c h l o r i d e s .

REFERENCE:

I. T. W. R i c h a r d s and H. G. P a r k e r , Z. a n o r g . C h e m . 1 3 , 81 (1897); W. Biltz and G. F . Hiittig, Z . a n o r g . a l l g . C h e m . 119, 116 (1921); W. Biltz and W. K l e m m , Z . p h y s . C h e m . 110, 331 (1924); W. D. T r e a d w e l l and T. Z i i r r e r , Helv. C h i m . A c t a 1 5 , 1271 (1932); Κ. K. K e l l e y and G. E . M o o r e , J . A m e r . C h e m .