11 Synthesis of a Beryllosilicate with the Structure of Analcime
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S. UEDA and M . KOIZUMI The Institute of Scientific and Industrial Research, Osaka University, Suita, Osaka 565, Japan
A crystalline phase of beryllosilicate with analcime structure was obtained under hydrothermal conditions from starting material of composition Na Βe Si O · NaCl. An analcimelike phase was obtained as a nearly pure phase at 200°C. A small amount of sodium chloride coexisted with the above phase. The lattice constant was a = 13.35 ± 0.01A. The refractive index was 1.519 ± 0.002, higher than that of nor mal analcime. The broad endothermic peak, indicating the dehydration of zeolitic water, was observed in the tempera ture range from 150° to 500°C on a DTA curve. The speci men showed little change of structure on heating to 500°C. These results indicate that a beryllosilicate with the anal cime structure was prepared by direct synthesis. 3
1.5
5
13
T n naturally occurring zeolites, the extensive isomorphous replacement of aluminum, which is situated in the tetrahedral sites of the frame work, by cations other than silicon is quite rare. Two examples of substitution by phosphorus have been reported by McConnell (4) for viseite [CaioNa2(Al2oSi6Pio(H )i2)096(H 0)i6] and kehoeite [Zn .5Ca2.5(Ali Pi (H )i )096(H 0)32], which are isostructural with analcime (NaAlSi 0 · H 0 ) . On the basis of the occurrence of these phosphate zeolites in nature, Barrer et al. (2) attempted to synthe size zeolites consisting of alumino- and silicophosphates hydrothermally, but no crystalline phase with zeolitic structure was obtained in their experiments. On the other hand, they (J) earlier had succeeded in ob taining various species of gallogermanates with zeolitic structure in place of aluminosilicate. Their results demonstrated the isomorphous replace ments of Ga ^± A l and Ge ^ Si between gallogermanate and aluminoA
3
5
6
2
6
6
3
6
2
2
2
135 In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
136
MOLECULAR SIEVE ZEOLITES
silicate. I n spite of this fact, t h e n a t u r a l o c c u r r e n c e of
1
gallogermanate
zeolites has n e v e r b e e n o b s e r v e d . An
example
zeolitic
of A l ^ ± B e
structure
is
given
substitution i n the aluminosilicate w i t h for
helvine.
The
structure
of
helvine
( M n 4 B e S i O i 2 S ) , s i m i l a r to sodalite ( N a 4 A l S i O i C l ) , is c o m p o s e d of 3
3
3
3
2
the t h r e e - d i m e n s i o n a l f r a m e w o r k w i t h b o n d i n g of ( B e 0 )
and
4
tetrahedra ( 5 ) .
(Si0 ) 4
I n o r d e r to k e e p t h e electrostatic c h a r g e b a l a n c e , A l
is
3 +
r e p l a c e d b y B e , N a b y M n , a n d C I " b y S ", a l t h o u g h e a c h s u b s t i t u t i o n 2 +
+
2 +
2
p a i r i n v o l v e s changes of b o t h size a n d charge.
I n the case of s o - c a l l e d
tugtupite [ N a A l B e 2 S i 0 ( C l , S ) ] , formerly named beryllosodalite b y 8
2
8
2 4
2
S e m e n o v a n d B y k o v ( 8 ) , the s t r u c t u r e consists of l i n k e d M 0
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with M =
B e , A l , a n d S i as t h e m e t a l l i c cations ( 3 ) .
tetrahedra
4
T h e result proves
that t h e t y p e of i s o m o r p h o u s r e p l a c e m e n t d e s c r i b e d b e l o w takes p l a c e b e t w e e n sodalite a n d s o - c a l l e d t u g t u p i t e . 2A1 + B e + S i + 3
2
4
F r o m these facts, i t is reasonable, t h e n , t h a t some b e r y l l o s i l i c a t e s m a y b e d i s p o s e d to f o r m a f r a m e w o r k w i t h l a r g e z e o l i t e - l i k e cavities. T h e p u r p o s e of this s t u d y has b e e n to synthesize n e w c r y s t a l l i n e phases of b e r y l l o s i l i c a t e w i t h z e o l i t i c structure. T h e first a t t e m p t w a s m a d e to o b t a i n a phase w i t h the a n a l c i m e - l i k e structure, b e c a u s e i t is k n o w n that a n a l c i m e is the most e a s i l y c r y s t a l l i z e d z e o l i t i c phase u n d e r h y d r o t h e r m a l c o n d i t i o n s i n the system N a 0 - A l 0 - S i 0 - H 0 . 2
2
3
2
2
Experimental S t a r t i n g M a t e r i a l . T h e c o m p o s i t i o n of b e r y l l o s i l i c a t e e q u i v a l e n t to ideal analcime m a y be written N a B e i . S i 0 · aq, if A l i n analcime ( N a A l S i 0 · a q ) is r e p l a c e d b y B e to k e e p the electrostatic b a l a n c e as s h o w n b y the f o r m u l a of 2 A 1 ^± 3 B e . S a h a ( 7 ) , w h o s y s t e m a t i c a l l y s t u d i e d the phase s t a b i l i t y of a n a l c i m e , c o n c l u d e d that t h e y f o r m as a stable phase over the w i d e range f r o m n e p h e l i n e c o m p o s i t i o n ( N a A l S i 0 ) to a l b i t e ( N a A l S i 0 ) . S i n c e the s o d a l i t e c o m p o s i t i o n corresponds to t h a t of 3 n e p h e l i n e ( N a A l S i O i ) + s o d i u m c h l o r i d e ( N a C l ) , i t is possible f o r the a n a l c i m e w i t h n e p h e l i n e c o m p o s i t i o n to f o r m i n association w i t h s o d i u m c h l o r i d e f r o m the s t a r t i n g m a t e r i a l w i t h sodalite c o m p o s i t i o n . I f the r e p l a c e m e n t 2 A 1 ^± B e S i takes p l a c e i n sodalite, as seen i n the case of s o - c a l l e d t u g t u p i t e , the f o r m u l a of the a l u m i n u m - f r e e e n d m e m b e r of sodalite w i l l b e g i v e n as NaJBei.sSL^OiaCl. C o n s e q u e n t l y , s t a r t i n g m a t e r i a l s w i t h the c o m p o s i t i o n of N a B e i . S i 0 a n d N a B e i . S i . O i · N a C l w e r e p r e p a r e d as d e s c r i b e d b e l o w . C a l c u l a t e d amounts of S n o w t e x - O s i l i c a s o l ( N i s s a n C h e m i c a l I n d u s t r y C o . , L t d . ) , IN solutions of N a O H a n d N a C l , a n d p o w d e r e d B e O w e r e m i x e d . T h e m i x t u r e was s t i r r e d v i g o r o u s l y a n d e v a p o r a t e d to dryness. T h e p r o d u c t o b t a i n e d w a s g r o u n d to fine p o w d e r to m a k e i t homogeneous. N o 5
2
2
6
6
3+
2 +
4
3
8
3
3
3
2
3+
2 +
5
3
5
4
5
2
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
4 +
2
6
11.
UEDA
AND
KOIZUMI
Beryllosilicate
with Structure
137
of Analcime
d i f f r a c t i o n peaks w e r e o b s e r v e d i n the x - r a y p o w d e r p a t t e r n of t h e m i x t u r e except those f o r b e r y l l i a . Techniques of Hydrothermal Synthesis. I n e v e r y r u n , the m a t e r i a l s w e r e c o n t a i n e d i n s m a l l sealed s i l v e r tubes to p r e v e n t selective l e a c h i n g . A s m a l l a m o u n t of d i s t i l l e d w a t e r w a s a d d e d b e f o r e t h e t u b e w a s sealed. T h e t y p e of pressure vessel u s e d w a s t h e test t u b e ( 6 ) . M o s t of the runs w e r e m a d e i n the pressure—temperature r a n g e of 1000 bars ( H 0 ) a n d 1 5 0 ° - 4 0 0 ° C for 1-3 weeks. T h e c h a r g e w a s q u e n c h e d after the r u n . T h e p r o d u c t s w e r e i d e n t i f i e d b y x-ray d i f f r a c t i o n t e c h n i q u e s , pétrog r a p h i e m e t h o d s , a n d d i f f e r e n t i a l t h e r m a l analysis. 2
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Results and
Discussion
F r o m the s t a r t i n g m a t e r i a l w i t h the c o m p o s i t i o n of N a B e i . S i 0 6 , 5
fine-grained
2
crystals w i t h a n a l c i m e - l i k e structure w e r e o b t a i n e d o n l y i n
the t e m p e r a t u r e r a n g e f r o m 175° to 2 2 5 ° C , associated w i t h b e r y l l i a a n d u n k n o w n phases.
E x c l u d i n g the x - r a y reflections f o r the latter 2 phases,
the x - r a y p o w d e r d a t a for the p r o d u c t are t a b u l a t e d i n T a b l e I. T h e l a t t i c e constant: a = 0.002.
The
specimen
was
13.35 ± obtained
0.01A; r e f r a c t i v e i n d e x : 1.519
±
from
of
the
starting material
N a B e i . S i 0 , at 2 0 0 ° C a n d 1000 bars ( H 0 ) f o r a w e e k . 5
2
6
2
T h e d i f f r a c t i o n p a t t e r n w a s almost i d e n t i c a l w i t h t h a t of n o r m a l a l u m i n o s i l i c a t e a n a l c i m e . T h e l a t t i c e constant w a s c a l c u l a t e d t o b e a 13.35 ±
=
0.01A b y i n d e x i n g t h e x - r a y reflections, a s s u m i n g t h a t t h e p h a s e
has c u b i c s y m m e t r y . T h e v a l u e is s l i g h t l y s m a l l e r t h a n the average one, 13.6A, for n o r m a l a n a l c i m e ( 7 ) .
T h e crystals w e r e o p t i c a l l y i s o t r o p i c
a n d the r e f r a c t i v e i n d e x w a s 1.519 ± a n a l c i m e , 1.48.
T h e s e differences
0.002, h i g h e r t h a n t h a t of n o r m a l
i n the v a l u e of l a t t i c e constant
and
r e f r a c t i v e i n d e x m a y result f r o m t h e existence of b e r y l l i u m o c c u p y i n g a Table I.
X - R a y D a t a for the Beryllosilicate with Analcime Structure
hkl
d(A)
211 200 321 400 332 422 431 521 440 611 620 631 543 640
5.43 4.71 3.56 3.33 2.845 2.724 2.618 2.436 2.361 2.167 2.114 1.968 1.888 1.853
I
hkl
d(A)
I
31 5 6 100 70 17 27 24 14 32 5 7 6 28
633 642 732 800 741 820 822 831 842 761 664 754 932 941
1.817 1.787 1.696 1.670 1.646 1.621 1.573 1.551 1.458 1.440 1.424 1.408 1.378 1.347
23 8 46 17 18 11 9 24 7 20 12 16 29 11
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
138
MOLECULAR SIEVE ZEOLITES
1
p a r t of t h e t e t r a h e d r a l sites r e p l a c i n g s i l i c o n a n d a l u m i n u m i n the f r a m e w o r k of a n a l c i m e . F r o m the s t a r t i n g m a t e r i a l s w i t h the c o m p o s i t i o n of Na3Be1.5Si4.5O12 · N a C l , t h e p h a s e w i t h a n a l c i m e - l i k e s t r u c t u r e w a s o b t a i n e d also i n the t e m p e r a t u r e r a n g e f r o m 175° to 2 2 5 ° C . T h e d a t a of x - r a y d i f f r a c t i o n a n d r e f r a c t i v e i n d e x c o r r e s p o n d w i t h those for the b e r y l l i u m - b e a r i n g a n a l c i m e i n d i c a t e d i n T a b l e I. F r o m this s t a r t i n g m a t e r i a l , h o w e v e r , the 2 phases, sodium chloride a n d chkalovite ( N a B e S i 0 ) were observed i n addition 2
2
6
to the b e r y l l i u m - b e a r i n g a n a l c i m e . I n o r d e r to m a k e the c h k a l o v i t e phase d i s a p p e a r , r u n s w e r e m a d e o n the s t a r t i n g m a t e r i a l s w i t h c o m p o s i t i o n a l ranges f r o m Na3Be1.5Si3.0O10 · Downloaded by STANFORD UNIV on June 4, 2013 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch011
N a C l to Na3Be1.5Si7.5Oi8 · N a C l .
A t 200°C, berylhum-bearing analcime
associated w i t h a s m a l l a m o u n t of s o d i u m c h l o r i d e w a s o b t a i n e d f r o m the s t a r t i n g m a t e r i a l , Na3Be1.5Si5.0O13 · N a C l , after 1-2 weeks.
A s the
s i l i c a content of s t a r t i n g m a t e r i a l w a s r e d u c e d , c h k a l o v i t e a p p e a r e d w i t h the a n a l c i m e . Q u a r t z w a s o b s e r v e d i n s t e a d of c h k a l o v i t e for h i g h e r s i l i c a contents. S i n c e the z e o l i t i c w a t e r i n n o r m a l a l u m i n o s i l i c a t e a n a l c i m e is r e m o v e d g r a d u a l l y f r o m the c r y s t a l l a t t i c e b y h e a t i n g , a b r o a d e n d o t h e r m i c p e a k is o b s e r v e d o n the D T A p a t t e r n of the m i n e r a l , as i n d i c a t e d i n Figure 1 ( A ) . T h e D T A c u r v e for the synthetic p r o d u c t o b t a i n e d f r o m the c o m p o s i t i o n Na3Be1.5Si5.0O13 · N a C l , i n c l u d i n g b e r y l l i u m - b e a r i n g a n a l c i m e a n d a m i n o r a m o u n t of s o d i u m c h l o r i d e s , is i l l u s t r a t e d i n F i g u r e 1 ( B ) .
The
b r o a d e n d o t h e r m i c p e a k i n the t e m p e r a t u r e r a n g e b e t w e e n
and
150°
500 ° C indicates d e h y d r a t i o n of z e o l i t i c w a t e r c o n t a i n e d i n t h e b e r y l l i u m bearing analcime.
T h e e n d o t h e r m i c p e a k at 8 0 0 ° C r e s u l t e d f r o m
the
m e l t i n g of s o d i u m c h l o r i d e . S i m i l a r t h e r m a l d a t a w e r e o b t a i n e d for the p r o d u c t s consisting of b e r y l l i u m - b e a r i n g a n a l c i m e a n d either c h k a l o v i t e or quartz.
Figure 1. DTA curves for: (A) analcime from Maze, Niigata, Japan and (B) beryllosilicate obtained from the starting material with the composition Na Be Si O · NaCl at 200°C, 1000 bars (H 0) for 2 weeks 3
t
5
5
0
13
2
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
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11.
UEDA
AND
Beryllosilicate
KOIZUMI
with
Structure
of Analcime
139
Sodium chloride and chkalovite were thermally stable up to their melting points, which were determined to be about 800°C for sodium chloride and 1050°C for chkalovite by the D T A method. Since a broad peak indicating the dehydration of zeolitic water was not altered by other endothermic peaks resulting from melting of sodium chloride and chkalo vite, the existence of zeolitic water could be inferred from the D T A curve. As for the berylhum-bearing analcime, there is little difference be tween the diffraction patterns of the original specimens and those heated to 500°C, except for the lattice constant change from 13.35 to 13.02A. Therefore, one may assume little change in the crystal structure of the analcime during gradual dehydration. The accurate structural formula of the berylhum-bearing analcime cannot be given, because the data of chemical analysis are not available at the present stage of the investigation. Assuming that the substitution 2A1 ^± Be Si takes place in normal analcime as seen in the case of so-called tugtupite, however, the supposed formula of the berylliumbearing analcime is set down as NaieBesSi^OgoiHkO)^. It is uncertain whether chlorine is situated in the cavity of berylhumbearing analcime lattice. However, since there is no difference in lattice constant and refractive index between the berylhum-bearing analcime synthesized from the Cl-free material of NaBei. Si 06 and that from Na3Be1.5Si4.5O12 · NaCl and from Na3Be1.5Si5.0O13 · NaCl, it is unlikely for chlorine to occupy the cavity. The chlorine may, however, play a role as mineralizer in the crystallization process of berylhum-bearing analcime. 3+
2+
4+
5
2
Conclusion A beryllosilicate with the analcime structure can be prepared by direct synthesis. The lattice constant, refractive index, and D T A data are presented for the compound. These results indicate that beryllium may occupy the tetrahedral sites, replacing aluminum in the zeolite structure. Literature Cited (1) Barrer, R. M., Baynham, J. W., Bultitude, F. W., Meier, W. M., J. Chem. Soc. 1959, 195. (2) Barrer, R. M., Marshall, D. J.,J.Chem. Soc. 1965, 6616. (3) Dano, M., Acta Cryst. 1966, 20, 812. (4) McConnell, D., Mineral. Mag. 1964, 33, 799. (5) Pauling, L., Z. Krist. 1930, 74, 213. (6) Roy, R., Tuttle, O. F., "Physics and Chemistry of the Earth," Ch. 6, Pergamon, London, 1956. (7) Saha, P., Am. Mineralogist 1961, 46, 859. (8) Semenov, Ε. I., Bykov, Α. V., Dokl. Earth Sci. Sect. English Trans. 1961, 133, 812. RECEIVED January 29,
1970.
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
