Chapter 41
Phase Identification of Hydrothermal Crystallization Products from M O-SiO -SnO -H O Gels or Solutions 2
2
2
2
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Edward W. Corcoran, Jr., J. M. Newsam, H. E. King, Jr., and D. E. W. Vaughan Exxon Research and Engineering Company, Route 22 East, Annandale, NJ 08801
A number of phases have been produced by hydrothermal crystallizations from M O-SiO SnO ~H O gels or solutions. The products of such syntheses are frequently multiphasic, complicating attempts at composition and structure definition. Preliminary microcrystal diffraction experiments using synchrotron X-rays and quantitative treatment of in-house powder X-ray diffraction data have enabled phase identification and facilitated the isolation of two largely phase-pure materials. Infrared spectroscopy and solid state Si and Sn nmr are consistent with the presence of octahedrally coordinated tin and tetrahedrally coordinated silicon in these phases. 2
2
2
2
29
119
The r e c e n t d e s c r i p t i o n s o f t h e ALPO-n, SAPO-n a n d MeAPO-n f a m i l i e s o f m i c r o p o r o u s m a t e r i a l s i l l u s t r a t e t h a t h y d r o t h e r m a l s y n t h e s e s c a n a f f o r d a wide a n d d i v e r s e range o f f o u r - c o o r d i n a t e framework s t r u c t u r e s b a s e d on n e a r r e g u l a r t e t r a h e d r a [ 1 , 2 ] . As b u i l d i n g b l o c k s , o c t a h e d r a and t e t r a h e d r a c a n a l s o be combined, i n v a r i o u s p r o p o r t i o n s , i n t o a v a r i e t y o f s t r u c t u r e types [3,4]. R e f l e c t i n g t h e c o n d i t i o n s u s e d f o r c o n v e n t i o n a l s y n t h e s i s [ 3 , 4 ] , most o f t h e s e s t r u c t u r e s a r e condensed, w i t h l i t t l e a c c e s s i b l e p o r e volume. T h e r e a r e , however, examples o f b o t h s y n t h e t i c [57] and n a t u r a l m a t e r i a l s [8-11] t h a t have m i c r o p o r o u s c r y s t a l l i n e s t r u c t u r e s . Further, the formation chemistry of s i l i c a t e s and a l u m i n o s i l i c a t e s [12,13] i l l u s t r a t e s t h a t t h e more open s t r u c t u r e s a r e g e n e r a l l y p r o d u c e d u n d e r r e l a t i v e l y m i l d c o n d i t i o n s . Open o c t a h e d r a l - t e t r a h e d r a l s t r u c t u r e s w i t h l a r g e p o r e systems might t h e r e f o r e a l s o be a c c e s s i b l e under a p p r o p r i a t e low t e m p e r a t u r e h y d r o t h e r m a l conditions. 0097-6156/89/0398-0603$06.00/0 o 1989 American Chemical Society Occelli and Robson; Zeolite Synthesis ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
ZEOLITE SYNTHESIS
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604
As an e x e m p l a r y system, we have been s t u d y i n g c r y s t a l l i z a t i o n s from s t a n n o s i l i c a t e g e l s and s o l u t i o n s w i t h v a r i o u s c o m p o s i t i o n s i n t h e s y s t e m M20-Si02~Sn02-H20 (M = L i , Na, K, C s ) . P r e v i o u s l i t e r a t u r e d a t a ( d i s c u s s e d below) s u g g e s t t h a t t h e r e i s scope f o r a r a n g e o f s t r u c t u r e t y p e s t o be p r o d u c e d i n t h i s system, b a s e d b o t h on p o s s i b l e v a r i a b i l i t y i n t h e r e l a t i v e p r o p o r t i o n s o f o c t a h e d r a and t e t r a h e d r a , a n d a p o s s i b l e d i v e r s i t y i n t h e manners i n w h i c h t h e y c a n be i n t e r l i n k e d . B r o a d scope i n t h e p o s s i b l e p r o d u c t s t r u c t u r e s , however, i m p l i e s t h a t t h e s i m u l t a n e o u s c r y s t a l l i z a t i o n o f more t h a n one phase might be common. I n i t i a l s c o p i n g e x p e r i m e n t s a r e t h e r e f o r e l i k e l y t o be c o m p l i c a t e d by p r o b l e m s a s s o c i a t e d w i t h p r o d u c t m u l t i p h a s i c behavior. In t h e p r e s e n t r e p o r t we d e s c r i b e i n i t i a l s y n t h e s e s i n the M20-Si02-Sn02-H20 s y s t e m . We i l l u s t r a t e how developments i n c h a r a c t e r i z a t i o n t e c h n i q u e s can f a c i l i t a t e the i d e n t i f i c a t i o n o f new p h a s e s i n t h e s e t y p e s o f s y s t e m s . We m e n t i o n u s e o f s y n c h r o t r o n X - r a d i a t i o n i n m i c r o c r y s t a l d i f f r a c t i o n experiments, f u l l p r o f i l e f i t t i n g o f 'in-house' powder X - r a y d i f f r a c t i o n d a t a , and i n f r a r e d a n d s o l i d s t a t e S n and S i nmr s p e c t r o s c o p i e s . 1 2 9
2 9
B a c k g r o u n d on C r y s t a l l i n e
Stannosilicates
Several minerals containing octahedrally-coordinated t i n and t e t r a h e d r a l l y - c o o r d i n a t e d s i l i c o n a r e known ( T a b l e 1). In a d d i t i o n t o t h e n a t u r a l l y - o c c u r r i n g m a t e r i a l s , hydrothermal c r y s t a l l i z a t i o n s a t higher temperatures (T>350°C) have been r e p o r t e d [14-18], i n c l u d i n g t h e s y n t h e s e s o f s i x sodium s t a n n o s i l i c a t e s (Na2Sn3SÎ9025 NaeSn7Si2o058/ Na4Sn Siio032, N a i o S ^ S i g C ^ f N a i s S n e S i ^ C ^ g , Na2Sn2Si60i7) [15-17], t h r e e c a l c i u m s t a n n o s i l i c a t e s (CaSnSi05, CaSnSÎ3C>9, CaSnSi309 · 2H2O) [ 1 4 ] , a n d a p o t a s s i u m s t a n n o s i l i c a t e (K2SnSi3C>9) [18] . P r e s u m a b l y b e c a u s e o f t h e s e v e r i t y o f t h e r e a c t i o n c o n d i t i o n s employed, o n l y one o f these phases i s r e p o r t e d t o c o n t a i n water [ 1 4 ] . f
5
Table Name malayaite brannockite sorensenite eakerite asbecasite pabstite stokesite sverigeite
1,
s t a n n o s i l i c a t e
Minerals*
Approximate Composition
Reference
CaSnSiOs (K,Na) Li3Sn2Sii203o Na4SnBe2Si60is · 2H2O Ca2SnAl SÎ60i6 (OH) • 2H 0 Ca3Tio .eSno .2As6SÎ2Be202o BaSn.77T i .23S13O10 CaSnSÎ3C>9 · 2H2O NaMgMnBe2SnSi30i20H 2
2
2
19 20 21 22 23 24 25 26
*Arandisite i s reported to be a stannosilicate, but no s t r u c t u r a l or compositional data are available [27] . Other minerals which may contain t i n have also been reported; examples include y f t i s i t e [28] and varlamoffite [29].
Occelli and Robson; Zeolite Synthesis ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
41. CORCORAN ET AL.
Hydrothermal Crystallization Products
605
Some m a t e r i a l s f o r w h i c h s t r u c t u r a l d a t a a r e a v a i l a b l e a r e l i s t e d i n T a b l e 2. I n c o r p o r a t i o n o f t i n i n t o t e t r a h e d r a l frameworks has been r e p o r t e d [ 3 0 ] , a l t h o u g h d e t a i l s about t h e l o c a l t i n c o o r d i n a t i o n a r e s t i l l l a c k i n g .
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Synthesis of Stannosilicates The r e a c t a n t s t i n ( I V ) c h l o r i d e , a l k a l i - m e t a l b a s e , and c o l l o i d a l s i l i c a (Ludox-HS40) were t h o r o u g h l y m i x e d a t room t e m p e r a t u r e , a c c o r d i n g t o t h e r a t i o s 2-5M20:Sn02:410SiO2:80-100H2O, f o r e a c h s y n t h e s i s [ 4 7 ] . C a b o s i l (fumed s i l i c a ) and sodium s t a n n a t e were a l s o u s e d a s r e a c t a n t s . The r e s u l t i n g g e l s were h e a t e d ( w i t h o u t c o l d - a g i n g o r a g i t a t i o n ) i n s t a i n l e s s s t e e l autoclaves a t temperatures o f between 150°C and 225°C a n d a t a u t o g e n o u s p r e s s u r e s f o r p e r i o d s r a n g i n g from 3 days t o 10 weeks. The r e a c t i o n v e s s e l s were t h e n c o o l e d t o room t e m p e r a t u r e a n d t h e p r o d u c t ( s ) removed a n d washed w i t h w a t e r . Crystalline m a t e r i a l s g e n e r a l l y r e s u l t e d b u t , as w i t h z e o l i t e s y n t h e s e s , s i m u l t a n e o u s c r y s t a l l i z a t i o n o f two o r more p h a s e s i s common. T h i s i s e v i d e n t i n T a b l e 3 which l i s t s m a j o r p r o d u c t s from a r a n g e o f s t a r t i n g c o m p o s i t i o n s a n d c o n d i t i o n s w i t h i n t h e system. When a g e l w i t h M = Na a t a c o m p o s i t i o n o f 2Na2O:SnO2:4SiO2:80H2O i s h e a t e d f o r t h r e e weeks a t 200°C a s t a n n o s i l i c a t e phase, l a b e l l e d A, r e s u l t s . The optimum r e a c t i o n g e l f o r p r o d u c i n g t h i s compound i s o b t a i n e d b y m i x i n g an aqueous sodium h y d r o x i d e s o l u t i o n w i t h 40% c o l l o i d a l s i l i c a (14.9g NaOH i n 20g d i s t i l l e d H 2 O ; 27.4g Ludox-HS40) f o l l o w e d b y a d d i t i o n o f t i n ( I V ) c h l o r i d e i n w a t e r (16.Og SnCl4«5H20 i n 20g d i s t i l l e d H 2 O ) . Chemical a n a l y s e s o f phase A m a t e r i a l s i n d i c a t e an a p p r o x i m a t e f o r m u l a o f NasSn5Sii2036 · nH20. H i g h e r l e v e l s o f b o t h sodium and s i l i c a p r o d u c e d a d i f f e r e n t phase ( d e s i g n a t e d L) a t 200°C, t h o u g h much l o n g e r s y n t h e s i s t i m e s were n e c e s s a r y . Samples o f t h i s m a t e r i a l t y p i c a l l y c o n t a i n e d an amorphous component w h i c h p e r s i s t e d even a f t e r c r y s t a l l i z a t i o n p e r i o d s o f 6 weeks. Powder X - r a y d i f f r a c t i o n a n d s c a n n i n g e l e c t r o n m i c r o s c o p y d a t a on phase L m a t e r i a l s s u g g e s t t h a t i t may have a l a y e r e d s t r u c t u r e . When M = Na, L i (1:1) c r y s t a l l i z a t i o n o f a g e l ( w i t h c o m p o s i t i o n L 1 2 O :Na20 : Sn02 : 4SiC>2 : 8 O H 2 O ) f o r 3 weeks a t 200°C y i e l d s a n o t h e r s t a n n o s i l i c a t e phase l a b e l l e d B. The r e a c t i o n g e l f o r t h i s m a t e r i a l i s c r e a t e d by combining aqueous b a s e a n d s i l i c a w i t h d i s s o l v e d t i n ( I V ) c h l o r i d e (11.3g NaOH a n d 3.9g LiOH i n 20g d i s t i l l e d H 0 w i t h 27.9g Ludox-40; 16.3g SnCl4*5H20 i n 20g d i s t i l l e d H 2 O i s a d d e d ) . M i x t u r e s c o n t a i n i n g p r e d o m i n a n t l y phase Β were a l s o r e c o v e r e d from M = Na g e l s when t h e s i l i c a s o u r c e was varied. Phase Β e x h i b i t e d s p h e r i c a l a g g r e g a t e s o f m i c r o c r y s t a l s i n scanning e l e c t r o n micrographs. An a p p r o x i m a t e p h a s e Β f o r m u l a o f Nai6SneSi24072 ·ηΗ2θ was i n d i c a t e d by c h e m i c a l a n a l y s i s . 2
Occelli and Robson; Zeolite Synthesis ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
Occelli and Robson; Zeolite Synthesis ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
Sorensenite Malayaite Benitoite-type Eakerite Wadeite-type Wadeite-type Na,Sn-Silicate Na,Sn-Silicate Na,Sn-Silicate Asbecasite Varlamoffite Stokesite N i g e r i t e - 24 Benitoite-type Grenat-type Wadeite-type Wadeite-type Wadeite-type Wadeite-type Na,Sn-Germanate Na,Sn-Germanate Na,Sn-Germanate Na,Sn-Germanate Na,Sn-Germanate
Name
2
2
2
4
0
2
2
3
2
3
2
2
4
4
2
4
6
8
4
3
2
4
3
3
2
2
2
2
1 4
6
3
10
5
5
4
9
9
0
9
9
9
5
5
2 6
6
3
8
3
2
6
8
3
2
1 6
9
9
9
20
8
30
1 6
1 2
3
1 2
2
2
1 8
1 8
9
6
6
1 8
2
6
2
2
2
2
2
12
l i 5
1 8
2
4
2
4
4
6 7
30
2
2
2
2
22
2
2
20
5
20,.698 (17) 7,.149 6..728 (5) 15,.892 (7) 6..860 6..943 20..883 (2) 10..576 (3) 7..344 (1) 8..36(2) 4..741 14..4 65 18..826 (10) 6..894 (5) 12..430 7..288 12..082 12..305 12..351 5,.778 6,.951(1) 10,.252 (1) 6..956 9,.023 (4)
a (A) 7,.442 (5) 8,.906 6,.728 (5) 7,.721 (3) 6..860 6..943 13..794 (1) 10..183 (2) 7..344 (1) 8..36(2) 4..741 11..625 18..826 (10) 6..894 (5) 12..430 7..288 12..082 12..305 12..351 11..615 20..062 (2) 15..504 (2) 5,.362 9..023 (4)
b (A)
α
Materials
12,.037 (11) 90, 6,.667 90, 90, 9,.838(5) 7,.438 (3) 90, 90. 10,.120 90, 10,.040 90. 5,.231 (1) 7..340 (2) 90. 87..85(1) 7..344 (1) 15..30(3) 90. 3..139 90 90. 5..235 18..826 (10) 17..508 (3) 90. 10,.233(5) 90. 12..430 90. 10..472 10..181 90. 10..205 90. 90. 10..134 107..62 5..540 90. 5,.370 (1) 6,.413(1) 96..89(1) 90. 20,.790 90. 21,.933 (7)
c (A)
for which S t r u c t u r a l D e t a i l s are Known
Some S t a n n o s i l i c a t e s . S t a n n o g e r m a n a t e s a n d R e l a t e d
Sn Be S i 0 (H 0) Sn S i 0 Sn S i 3 0 Sn A l S i 0 (0H) (H 0) Sn S i 0 Sn S i 0 Sn S i 0 H0 Sn S i 0 Sn S i 0 T i . Sn . A s S i Be O A l Sn Si 0 (H 0) . Sn S i 0 (H 0) . 9 Sn F e . Ζηχ. O (OH) Sn Ge 0 Ca Sn Ge 0 Sn Ge3 0 Sn Ge 0 Sn Ge 0 Sn Ge 0 Sn Ge 0 (OH) Sn Ge 0 (H 0) Sn Ge O (OH) Sn G e O (OH) Sn S i 0
8
4
2
Na Ca Ba Ca K Rb Na Na Na Ca Fe Ca Al Ba Na Cs K Rb Tl Na Na Na Na Na
2.
Formula
Table
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117..28(6) 113..4 90. 101..34(3) 90. 90. 90. 92.,90(2) 87.,85(1) 90. 90 90. 17.,508(3) 90. 90. 90. 90. 90. 90. 75..75 90. 107..56(1) 106..21 90.
β
