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The Crystal Structures of Several Metal Aluminophosphate Molecular Sieves
269
P.J. Grobet et al. (Editors) /Innovation in Zeolite Materials Science ElsevierSciencePublishers B.V.,Amsterdam- Printed in The Netherlands
THE
CRYSTAL
STRUCTURES OF SEVERAL MOLECULAR SIEVES
METAL
ALUMINOPHOSPHATE
J. M. BENNETT and B. K. MARCUS' Union Carbide Corporation, Tarrytown Technical Center, Tarrytown, New York, 10591. U. S. A.
ABSTRACT The crystal structures of CoAPO-44, CoAPSO-44, MAPSO-46, CoAPSO-47 and CoAPO-50 were determined from single crystal x-ray data. All five structures have the tetrahedral framework phosphorus or silicon alternating with the tetrahedral aluminum or the metal (cobalt or magnesium). The crystal structures of the 44's and 47 are topologically similar to the mineral chabazite, but with framework distortions which reduce the symmetry from rhombohedral to triclinic (P 1bar). The framework topologies of MAPSO-46 and CoAPO-50 are novel and form a new series of structures based on capped six membered rings with a unidimensional 12-ring channel system having a free aperature between 7A and 8A crossed-linked through 8 rings. CoAPO-50 is the end member of the series and is built from double four rings (a six ring capped top and bottom) only previously observed in Linde type A zeolite. Unlike the other metal aluminophosphate structures described here, the cobalt in CoAPO-50 occupies both the same crystallographic site as aluminum and a unique tetrahedral site. INTRODUCTION The aluminophosphate-based molecular sieves are an important new class of catalyst and 2
Included are families designated AlPO4-n
adsorbent materials I.
,
SAPO-n
3
,
MeAPO-n
4
,
MeAPSO-n I, etc., where -n denotes a specific structure type. The synthesis conditions involve crystallizing a gel between 100°C and 250°C in the presence of an organic template under hydrothermal conditions. The resulting solid may be calcined to remove both the template and water to allow the microporous nature of the material to be utilized. The crystal structures of a number of aluminophosphate-based molecular sieves and other I: I alumino phosphate structures have been reported including AlPO4-55, 7
8
9
10
11
12
AlPO4_11
6
,
13
AIPO4-12, GaPO4-14, AIPO4-15, AlPO4-16 , AlPO4-17 , AlPO4-21 , AIPO4-33 , 14 15. AIP0 and SAPO_34 The structures of the aluminophosphate molecular sieves show 4-EN3 four coordinated aluminum and phosphorus oxide frameworks with occasional secondary coordination of some of the framework aluminum with non-framework species such as H20 or OH occluded in the cavities.
Of recent interest are the
MeAPO and
MeAPSO families 1.4,
tv
-a
Table 1 Crystallographic and pertinent information for the reported structures.
0
gamma
U.C. Volume
Space Group
R%
Rw%
89.990
119.980
2459
P1bar
9.6
10.0
8474
2968
89.993
89.989
119.984
2466
P1bar
9.8
10.1
8433
2901
26.8922
90
90
120
4080
P3c1
9.0
11.9
6809
3926
13.8132
14.9937
89.997
90.081
120.066
2474
P1bar
10.0
11. 3
5129
2637
12.7485
12.7485
9.0147
90
90
120
1269
P3bar
8.2
7.1
868
849
13.384
13.384
90
90
90
2397
F23
Structure Type
a(A)
b(A)
c(A)
alpha
beta
CoAPO-44
13.6346
13.6299
15.2804
90.006
CoAPSO-44
13.6440
13.6430
15.2940
HAPSO-46
13.2251
13.2251
CoAPSO-47
13.8022
CoAPO-50 AlP04-16
13.384
Analysis Type
Crystal Color / Size / Shape
6(C6H11NH2)·Co4.SAl13.5P18072·qHZO
Typical
Blue Rhomb 90 microns along an edge
CoAPSO-44 5(C6H11NHZ)·KO.3Co2.5Al16.5P15.0Si3.007Z·qHZO
Bulk
Blue Rhomb 70 microns along an edge
Structure Type CoAPO-44
MAPSO-46
Composition
Number Reflections I>sigma )3sigma
8(C3H7)ZNH'Mg6Al22PZ6SiZ011Z'qH20
Typical
Colorless Lozenge 90 microns along an edge
CoAPSO-47 6(C3H7)ZNH·COZ.5~l15.ZP13.7Si4.6072·qH20
Bulk
Blue Rhomb 70 microns along an edge
CoAPO-50
Bulk
Blue trigonal rod 70 microns long
3(C3H7)ZNH'co3Al5P8032·6.7HZO
Note: Analysis type indicates the source of the analysis. Bulk is the bulk analysis of the sample. Typical is an analysis of a sample expected to have the same composition as that used for the structural study.
271
including the materials studied here which contain cobalt or magnesium, aluminum, phosphorus and sometimes silicon in the tetrahedral framework. These compositions can be considered in 3
terms of occupancy by the Co+2 or Mg+2 in the crystallographically equivalent Al+ site and a 4
5
similar occupancy by Si+ in a p+ site in a hypothetical I: I aluminophosphate framework resulting in a net negative framework charge for each cobalt,
magnesium or
silicon
incorporated. The framework charge must then be balanced by the charge on the non-framework components.
The cobalt containing materials are royal blue, similar in color to a cobalt
containing Akermanite 16 in which cobalt occupies a tetrahedral framework position. EXPERIMENTAL The x-ray powder diffraction patterns of CoAPO-44, CoAPSO-44 and CoAPSO-47 resemble that given by chabazite but with reflections that violate the Rbar3m rhombohedral symmetry.
Calcination yielded powder patterns that were more similar to the pattern of a
calcined chabazite.
Single crystal x-ray techniques showed that the symmetry was triclinic,
space group Plbar, if the pseudo-hexagonal settings were maintained to simplify testing the cause of the distortions from rhombohedral symmetry. The x-ray powder diffraction patterns of' MAPSO-46 and CoAPO-50 indicated that the materials were new topologies with no known zeolite analogues.
Table 1 lists the unit cell dimensions, space groups, compositions, and other
pertinent information for all five materials. The chemical analyses are either from the bulk sample when pure and containing large crystals or from a pure sample expected to have a composition similar to that from which the single crystals were chosen. Syntheses were from the corresponding metal (silico)aluminophosphate gels containing the appropriate amine as the template'". The CoAPSO-44 gel also contained K+ ions. The single crystal X-ray data were collected either on a Picker KRlSEL diffractometer or an Enraf Nonius CAD4 diffractometer using monochromatized copper K« radiation, and the structures were solved and refined using the SDP programs. The data were not corrected for absorption. Refinement of the 44's and 47 were begun using idealised parameters for chabazite but with strict alternation of aluminum and phosphorus in the framework and no assumptions as to the position of the cobalt even though the chemical analyses were consistent with the cobalt being in the framework. The final R factor in all three determinations was 9 to 11 % for the framework and template, exclusive of occuluded water molecules and template hydrogen atoms, confirming that they all have a chabazite-like topology but with triclinic symmetry. In all three structures,
272
TABLE 2 Refined parameters for the framework atoms of CoAPO-44 Atom' x y PI 0.98631 0.76732 P2 0.33579 0.43622 P3 0.34051 0.91253 P4 0.23875 0.23478 P5 0.56581 0.89689 P6 0.09565 0.44260 P7 0.77402 0.01210 P8 0.10741 0.67160 P9 0.56667 0.66302 All 0.99884 0.23420 A12 0.31985 0.43057 Al3 0.34694 0.90083 Al4 0.75954 0.76858 Al5 0.56749 0.89473 Al6 0.10251 0.43631 Al7 0.22873 -0.00328 Al8 0.09792 0.66879 Al9 0.55708 0.65570 011 1.00660 0.29998 014 0.88507 0.79575 016 0.96650 0.63774 0.86423 0.13013 017 022 0.33505 0.40308 024 0.67368 0.66730 026 0.77399 0.52815 029 0.44713 0.54177 033 0.64646 0.05523 0.54435 0.10330 035 035' 0.35852 0.00902 038 0.20966 0.76705 041 0.87135 0.73811 044 0.70795 0.70108 047 0.19697 0.08534 049 0.64134 0.65224 053 0.44251 0.91540 055 0.61102 0.92324 057 0.65838 0.98321 059 0.44672 0.23447 062 0.77896 0.55594 066 0.05796 0.39827 068 0.97896 0.35124 068' -0.14202 0.41625 071 0.08300 0.88664 073 0.32367 0.97632 074 0.25642 0.13242 077 0.26298 -0.01203 081 0.00201 0.30808 083 -0.24373 0.23058 086 0.11664 0.55333 088 1.06343 0.67597 092 0.57210 0.46160 092' 0.64494 0.65189 095 0.57727 0.79167 099 0.60719 0.66122 I
Z
0.89044 0.57064 0.77642 0.88647 0.57055 0.77382 0.89213 0.55808 0.76804 0.90190 0.76496 0.56966 0.91073 0.76326 0.56289 0.90148 0.76287 0.57160 0.01955 0.12338 0.15380 0.88062 0.65435 0.15345 0.22994 0.80151 0.32190 0.44317 0.49999 0.54338 0.87206 1.01391 0.11014 0.84173 0.80054 0.64845 0.83566 0.22339 0.45384 0.67634 0.50094 0.46100 0.87427 0.83842 0.86363 1.02484 0.18310 0.23496 0.79454 0.65970 0.44686 0.48226 0.55608 0.67892
Table 1: Al sites contain 25% cobalt.
TABLE 3 Refined parameters for the framework atoms of CoAPSO-44 B(A2 ) 1. 21 2.11 1.51 2.11 1. 21 1.71 1.71 1.72 1. 21 2.11 2.81 2.72 2.21 2.11 1.61 2.32 1. 81 1.61 2.07 2.63 2.74 2.74 3.15 4.25 4.46 2.64 2.30 3.59 4.66 3.15 3.75 5.17 3.35 2.64 3.65 2.44 3.85 2.84 2.20 1. 33 1. 93 3.45 1.53 2.30 2.04 5.66 4.36 3.95 2.94 2.64 2.44 3.95 2.03 2.14
X
0.99011 0.33477 0.34098 0.23040 0.57051 0.09720 0.77433 0.10151 0.56603 1.01091 0.33234 0.33700 0.76264 0.56177 0.09617 0.22865 0.09718 0.55703 1.01267 0.89068 0.97064 0.86441 0.35496 0.69196 0.77675 0.45500 0.65081 0.54697 0.33497 0.22123 0.87151 0.72281 0.19061 0.64222 0.54980 0.61327 0.66241 0.45050 0.77519 0.05803 0.98517 -0.12311 0.09077 0.32161 0.25612 0.72141 0.00200 -0.24511 0.11301 1.05244 0.56697 0.66272 0.58188 0.59333
Y
0.77264 0.43209 0.90853 0.23256 0.89900 0.44058 0.01092 0.66788 0.66436 1.23078 0.43257 0.90774 0.76530 0.89368 0.43997 0.00020 0.67037 0.65627 0.29458 0.80457 0.63715 0.12847 0.40854 0.66757 0.52802 0.54734 0.06123 0.10804 0.00185 0.77248 0.74318 0.69726 0.08002 0.65360 0.08804 0.92756 0.98773 0.23652 0.55545 0.39785 0.35412 0.43403 0.88725 0.97353 0.13116 0.99943 0.30620 0.22938 0.55152 0.66583 0.45636 0.66348 0.79105 0.65064
Z
0.89398 0.56568 0.77465 0.88759 0.56917 0.77272 0.89537 0.55467 0.76692 0.90576 0.77038 0.57153 0.90558 0.76614 0.56681 0.89960 0.76252 0.56860 0.01411 0.12605 0.15308 0.88500 0.65375 0.16267 0.23175 0.79984 0.32612 0.45029 0.49563 0.54424 0.88152 1.01434 0.11146 0.84398 0.20093 0.64874 0.84139 0.22861 0.45816 0.67112 0.50606 0.46301 0.87415 0.83231 0.85962 0.97606 0.18402 0.22370 0.79221 0.66184 0.43804 0.49625 0.55432 0.67474
B(A2 ) 2.02 2.32 2.21 3.22 1. 51 1.71 2.12 3.62 1. 51 2.92 1.62 1.82 2.02 2.82 2.12 2.62 1.62 2.52 1.25 2.25 1. 57 3.08 4.03 2.22 2.77 1.16 1. 37 2.01 2.09 3.33 3.07 5.62 2.40 2.37 3.43 2.20 1.38 2.37 1.82 1.03 1.72 2.69 1.23 1.44 2.77 5.75 4.56 3.70 1.7.0 1.96 3.56 2.29 1.97 1.82
Table 2: Al sites contain 13% cobalt. P sites contain 17% silicon.
273
there is no crystallographic evidence for the cobalt being anywhere but in the framework occupying an equivalent tetrahedral site with aluminum.
The aluminum/cobalt to oxygen
distances varied from 1.7..\ to 1.9..\ suggesting ordering; however no suitable ordering scheme could be developed even for CoAPO-44 which has the highest cobalt content corresponding to a uniform distribution of one cobalt and three aluminums around a phosphorus. In MAPSO-46 and CoAPO-SO, the framework topologies were initially determined by a combination of modeling and direct methods. In CoAPO-50 the cobalt was initially assumed to occupy the same crystallographic site as the aluminum.
However, the non-phosphorus
tetrahedral site along the threefold axes had four oxygen bond distances of 1.95..\ and was therefore redefined as cobalt, the remaining cobalt was randomly distributed in the same crystallographic site as the aluminum. The final x-ray framework composition C03AISP 8032 is consistent with the bulk chemical composition C03AIsP8°32' 3(C3H7)2NH' 6. 7H 0. RESULTS/DISCUSSION Chabazite-like Materials: The chabazite-type framework topology is a three dimensional arrangement of double six-rings linked together by four rings. The symmetry of chabazite is rhombohedral Rbar3m; however an ordered aluminosilicate mineral (Wilhendersonite
t
has triclinic symmetry, and
recent studies on several hydrated and dehydrated ion exchanged natural chabazites 18 have lower than rhombohedral symmetry. The reduction in symmetry is caused by distortion of the four membered rings. The partial occupancy of a tetrahedral site by cobalt might also be expected to distort the framework. analogue of chabazite (SAPO-34
15
)
The structure of a calcined silicoaluminophosphate
has rhombohedral symmetry suggesting that in this material
the inclusion of silicon into the tetrahedral framework does not distort the framework. Tables 2-4 show the refined parameters for CoAPO-44, CoAPSO-44, and CoAPSO-47. In the triclinic unit cell chosen, there are three chabazite cavities;
for both 44
materials, between one and two presumably protonated cyclohexylarnine molecules occupy either of two positions in each cavity (Figure I). The amino group has position disorder, such that the I, 3 and 5 positions are equally occupied by 1/3 of an amino group. The CoAPSO-44 structure has the potassium and cyclohexylamine molecules occupying similar positions in the cavities (Figure I), and both presumably balance the framework charge corresponding to the amount of cobalt and silicon in the structure. No attempt was made to determine the positions of the silicon in the tetrahedral framework, since it was felt that the cobalt sufficiently
274
Figure I. Part of a chabazite cage for both CoAPO-44 and CoAPSO-44 showing the upper of the two positions of the cyclohexylamine at the same height as three 4-rings in the chabazite cage. The lower cyclohexylamine. position is at the same height as the lower three 4-rings, which are only partially shown. The nitrogen atom of the amino group has positional disorder and points towards any of the three 8-rings. The position. in a chabazite cage, of the upper of the two potassiums in CoAPSO-44 is shown between the cyclohexylamine and the double six ring. The second potassium is in an equivalent lower position.
complicated the least squares refinement.
Both 44 structures contain water which was not
determined from these structural studies. The tetrahedral framework distortions of the 44's are similar, yet different from those of CoAPSO-47. The amounts of silicon and cobalt in the CoAPSO-44 and CoAPSO-47 are very similar while the two 44's differ greatly in the amounts of cobalt incorporated and only one(CoAPSO-44) has silicon incorporated. Since, in both 44 structures, the template molecule is the same and they occupy almost the same positions, which are different from those occupied by di-n-propylamine in CoAPSO-47, the suggestion must be made that the template or its position controls the framework distortions. In summary, these three 44 and 47 structures have a chabazite-like framework topology in which tetrahedral silicon and phosphorus randomly alternate with tetrahedral aluminum and cobalt, The upper limit to the amount of cobalt and silicon incorporated and the resulting maximum negative framework charge may be limited by the amount of positively charged species which can fit within the available void space.
There is sufficient space for two
cyclohexylamine rings to pack inside each chabazite cavity.
Since both potassium and
cyclohexylamine occupy similar locations in CoAPSO-44, the potassium is assumed to be equivalent to cyclohexylamine for the above argument.
The possible orientations for the
di-n-propylamine in the CoAPSO-47 are less well defined and, therefore, may not have the same maximum occupancy limit as the cyclohexylamines, but the equivalent (C + N) values for each template species suggest they should fill similar volumes in the channel system. The K+ in the CoAPSO-44 shows that the organic template is not the only species capable of balancing the net framework charge and neither rigorously defines the limiting value of the framework charge resulting from cobalt and silicon introduction.
275
CoAPO-50: Figure 2 is a stereo view of the CoAPO-50 topology showing the l2-rlng undimensional pore system and the interconnecting 8-rings lining the channel.
The structure can be
Figure 2. Stereo view oj CoAPO-50 topology down the c axis.
considered to be horizontal sheets of six rings held together vertically by tetrahedral atoms capping each six ring above and below it to form double four-rings. The number of vertical bonds holding the sheets together is small and may account for a lower thermal stability for this structure type as compared to most other aluminophosphate-based molecular sieve structure types.
Half of these vertical bonds are cobalt-oxygen-phosphorus bonds, the rest are
aluminum-oxygen-phosphorus bonds.
Figure 3 shows the excellent correspondence of the
calculated and observed powder patterns, and Table 5 shows the refined atom parameters.
~
/2
16
20
24 DEGREES 32 28
36
~
44
Figure 3. Calculated (a) and observed (b) powder patterns for CoAPO-50.
The observation that 66% of the cobalt occupies a special position in the structure, combined with the assumption that the remaining cobalt occupies the same crystallographic site as the aluminum requires that some of the four rings must contain two cobalt atoms, indirectly showing that cobalt-oxygen-phosphorus-oxygen-cobalt sequences are possible.
276 TABLE 4 Refined parameters for the framework atoms of CoAPSO-47 Atoml x 0.98911 PI P2 0.32683 P3 0.33246 P4 U.23897 P5 0.56096 P6 0.10606 P7 0.77613 P8 0.10921 P9 0.56451 All 1. 00124 A12 0.33172 Al3 0.34016 A14 0.77659 A15 0.56048 A16 0.10095 A17 0.23288 Al8 0.11556 Al9 0.55894 011 1.0221 014 0.8974 016 0.9795 017 0.8663 022 0.3437 024 0.7082 026 0.7701 029 0.4514 033 0.6633 035 0.5491 035' 0.3474 038 0.2178 041 0.8-752 044 0.7363 047 0.1957 049 0.6658 053 0.4391 055 0.6176 057 0.6865 059 0.4584 062 0.7891 066 0.0838 068 0.9954 068' -.1445 071 0.0937 073 0.3353 074 0.2468 077 0.2742 081 -.0163 083 -.2520 086 0.1144 088 1.0840 092 0.5775 092' 0.6462 095 0.5865 099 0.5885
y
0.76369 0.43838 0.89497 0.22828 0.89005 0.43993 1.00941 0.66954 0.66539 0.77212 0.43232 0.89509 0.78124 0.89314 0.45397 0.00105 0.67208 0.65829 1.2856 0.8102 0.6653 0.1187 0.3978 0.6905 0.5210 0.5414 0.0841 0.1203 0.0122 0.7767 0.7453 0.7277 0.0886 0.6724 0.8827 0.9331 0.9946 0.2365 0.5793 0.4255 0.3566 0.4136 0.8919 0.9917 1.1242 0.0026 0.2914 0.2271 0.5566 0.6648 0.4472 0.6418 0.7980 0.6451
TABLE 5 Refined parameters for the framework atoms of CoAPO-50
Z
B(A2 )
Atom!
0.89056 0.55599 0.77111 0.89212 0.55854 0.77469 0.89502 0.55405 0.77266 0.10399 0.76795 0.56808 0.89677 0.76965 0.56061 0.90512 0.77516 0.56518 1.0140 1.1339 1.1766 0.8610 0.6575 0.1848 0.2279 0.7836 0.3275 0.4603 0.5035 0.5231 0.8771 1.0103 0.1356 0.8258 0.8044 0.6559 0.8240 0.2074 0.4755 0.6750 0.5017 0.4430 0.8841 0.8399 0.8571 1.0147 0.1791 0.2121 0.8036 0.6607 0.4742 0.4933 0.5444 0.6772
1. 21 1.52 1.62 1.92 1.31 2.42 1. 31 1.62 1.92 1. 22 1.42 1. 22 2.42 1.92 1.52 1. 32 1.72 1.02 1. 38 1. 53 1.55 1.77 2.23 2.33 1. 21 1. 73 1. 31 2.17 1.39 1.92 1.28 2.89 3.45 3.15 1. 37 1.19 1.22 2.28 1.63 2.31 2.36 1.69 1.14 1.89 1.82 2.40 2.17 3.37 1.38 3.91 2.64 1. 35 1. 24 1. 74
PI P2 Col A12 03' 032 011 012 014 02
x 0.66666 0.32054 0.33333 0.85620 0.8599 0.3983 0.5442 0.1951 0.3333 0.3578
y
0.33333 0.85825 0.66666 0.32580 0.4419 0.2045 0.2286 0.5057 0.6666 0.9943
Z
0.18967 0.38432 0.18967 0.40070 0.5131 0.5240 0.2516 0.2326 0.9766 0.3518
B(A2 ) 1.81 1.72 2.25 1.98 1. 73 1. 21 1. 25 1.15 2.40 1.16
TABLE 6 Refined parameters for the framework atoms of MAPSO-46 Atom' x PI 0.66667 P2 0.19862 P3 0.46965 P4 0.20093 P5 0.46960 P6 0.00000 All 0.00000 Al2 0.46967 Al3 0.19875 Al4 0.46726 Al5 0.19352 Al6 0.66667 012 0.9846 016 0.0000 021 0.6875 022 0.7350 023' 0.9192 023 0.7826 032 0.1515 032' 0.1910 033 0.3389 034 0.1638 043 0.8976 044 0.3218 045 0.5189 045' 0.4884 054 0.1405 054' 0.1867 055 0.7279 056 0.9997 061 0.6666 065 0.7979
y
0.33333 0.18082 0.10767 0.96592 0.31962 0.00000 0.00000 0.31584 0.96524 0.11576 0.17290 0.33333 0.1174 0.0000 0.2336 0.0649 0.4727 0.2713 0.2587 0.0927 0.9936 0.2199 0.5052 0.0036 0.4365 0.2442 0.2616 0.0777 0.0750 0.8889 0.3333 0.4676
Z
0.06039 0.13165 0.19050 0.30722 0.36555 0.43771 0.06457 0.13168 0.18925 0.30775 0.36246 0.43950 0.5852 0.9957 0.0819 0.1160 0.1661 0.1759 0.1616 0.1748 0.1796 0.7555 0.7477 0.3158 0.3483 0.3316 0.3398 0.3187 0.3741 0.4222 0.0081 0.4151
B(A2 ) 1. 22 1. 62 1.02 1. 73 1.16 1.60 1.55 2.55 1.04 1.42 1.46 1.39 1.75 2.49 1.36 1.02 2.29 1.91 2.65 1.96 2.58 3.21 1. 74 1.95 1.15 2.85 1. 76 2.29 2.09 2.66 2.85 2.54
In Tables 2-6 the anisotropically refined tetrahedral atoms are given in the form of the isotropic equivalent displacement parameter.
, Table 4: AI sites contain 14% cobalt, P sites contain 25% silicon.
Table 5: AI site contains 17% cobalt.
277
Both 50 and 46 can be synthesised with di-n-propylarnine and the refinements show that the di-n-propylamine molecules occupy almost identical positions in the two structures: the nitrogen atom is centered in the 8-rings with the propyl groups radiating into the 12-ring channel. The configuration of the template was not sufficiently well refined to confirm the expected protonation of the amine to balance the expected framework charge. The 50 framework topology is an end member of a new series of hypothetical structures with MAPSO-46as another member. Prior to CoAPO-50, Linde Type A was the only molecular sieve structure built from double 4-rings (doubly capped 6-rings) but since has also been observed in AIPO4-1610. The 16 topology has been determined from synchrotron powder studies and consists of doubly capped 6-rings (double 4-rings) joined by single tetrahedra in a similar arrangement to that of a hypothetical tetrahedrally complete zunyite
l9
.
MAPSO-46: MAPSO-46 and CoAPO-50 are both built from capped six rings surrounding a large undimensional 12-ring channel. Figure 4 is a stereo view of the framework, showing the
Figure 4. Stereo view of MAPSO-46 topology down the c axis.
12-ring channels.
Figure 5 shows the relationship via a sigma transformation'" of the
six-ring in a double four-ring between the 50 and 46 framework topologies. Similar sigma expansions, adding single six rings, further increases the
c dimension giving rise to a
family of structures, all having a l2-ring pore opening interconnected through 8-rings. The sigma transformation of 50 to 46 may be the first such observation that does not result in the formation of a planar ring. The scattering factors for magnesium and silicon are similar enough to those of aluminum and phosphorous that the structure refined satisfactorily using the aluminum and phosphorous factors. By analogy with other studies and consistency with chemical analyses,
278
f5l;j
0fJ
(a)
~
(b)
(d)
(c)
Figure 5. Sigma transjormation of 50 into 46. (a) A representation of 50 showing the six-ring of the double four-ring involved in the sigma transformation. (b) Upper and lower segment of (a) produced by the sigma transformation. (c) Rotation of lower portion 60" necessary for bonding. (d) Final result showing unit present in the 46 topology.
the magnesium was assumed to occupy the same tetrahedral site as aluminum and the silicon as phosphorous. The final difference maps of MAPSO-46 and all other structures reported here, showed no tetrahedral position having a peak (positive or negative) larger than that given by an hydrogen atom.
Table 6 shows the refined atoms parameters. (b)
(a)
38
4
Figure 6 shows the
40
4
8
12
18
20
24
28 DEGREES 38 28
40
Figure 6. Calculated (a) and observed (b) powder patterns for MAPSO-46.
calculated and observed powder patterns; the differences in the two patterns are caused by incomplete modeling of the eight di-n-propylamine molecules since only six were located. CONCLUSIONS These five structure determinations yield conclusive evidence for the complete tetrahedral framework siting of the various metal atoms incorporated into the structures: aluminum, phosphorous, silicon, magnesium and cobalt. The sorption properties of -44 and -47 are similar to those expected for a chabazite topology. The sorption capacity of CoAPO-50 is
279
expected to be large, and the pore opening is similar in size, but not shape, to that of Linde Type X or Y. The 12-and 8-ring pore openings and large structural void volumes suggest that both -50 and -46 should have excellent sorption properties. The refinement and the chemical analyses of CoAPO-50 shows that the cobalt present in the framework replaces more than 1/4 of the aluminum present in a hypothetical I: 1 AJPO4 material. This means that some phosphorus atoms must have at least two cobalt atoms out of the 4 tetrahedral neighbors bonded to it through oxygens; futhermore, the structure must contain a significant number of four rings having only phosphorus and cobalt. The properties of such' an arrangement need to be studied. Thanks are given to J. J. Pluth, University of Chicago, for collecting the CoAPO-44 and CoAPSO-44 data, to L. M. King, W. C. Mercer, and L. D. Vail who synthesized and supplied the single crystals used in these studies, and to E. M. Flanigen, R. L.
Patton
and S. T. Wilson for their critical review of this manuscript. REFERENCES E. M. Flanigen, B. M. Lok, R. L. Patton and S. T. Wilson, Pure and Appi. Chern., 58 (1986) 1351-1358. 2 S. T. Wilson, B. M. Lok and E. M. Flanigen , U. S. Patent (1982) 4,310,440. S. T. Wilson, B. M. Lok, C. A. Messina, T. R. Cannan and E. M. Flanigen, J. Am. Chern. Soc.. 104 (1982) 1146-1147. 3 B. M. Lok, C. A. Messina, R. L. Patton, R. T. Gajek, T. R. Cannan and E. M. Flanigen, U.S. Patent (1984) 4,440,871. B. M. Lok, C. A. Messina, R. L. Patton, R. T. Gajek, T. R. Cannan and E. M. Flanigen, 4 S. T. Wilson and E. M. Flanigen, U.S. Patent (1986) 4,567,029. 5 J. M. Bennett, J. P. Cohen, E. M. Flanigen, J. J. Pluth, and J. V. Smith, ACS Symp. Ser. 218, (1983) 109-118. 6 J. M. Bennett, J. W. Richardson Jr., J. J. Pluth and J. V. Smith, Zeolites 7 (1987) 160-162. 7 J. B. Parise, J. Chern. Soc., Chern. Commun., (1984) 1449-1450. 8 J. B. Parise, J. Chern, Soc., Chern. Commun. (1985) 606-607. 9 J. B. Parise, Acta Crystallogr., C40 (1984) 1641-1642. J. J. Pluth, J. V. Smith, J. M. Bennett and J. P. Cohen, Acta Crystallogr., C40 (1984) 2008-2011 IO J. M. Bennett, Personal communication. 11 J. J. Pluth, J. V. Smith, and J. M. Bennett, Acta Crystallogr., C42 (1984) 283-286. 12 J. M. Bennett, J. P. Cohen, G. Artioli, J. J. Pluth and J. V. Smith, Inorg. Chem. 24 (1985) 188-193. J. B. Parise and C. S. Day, Acta Crystallogr., C41 (1985) 515-520. I3 P. R. Rudolf, C. Saldarriaga-Molina and A. Clearfield, J. Phys. Chern., 90 (1986) 6122-6125. 14 J. B. Parise in 'Zeolites' (Ed. B. Drzaj, S. Hocevar and S. Pejovnik) Elsevier, (1985) p. 271-278. 15 M. Ito, Y. Shimoyama, Y. Saito, Y. Tsurita, Y. and M. Otake, Acta Cryst., C41 (1985) 1698-1700 16 M. Kimata, Neuef. Yahrbuch Miner. Abh. 146 (1983) 221-241. 17 R. D. Peacor, P. J. Dunn, W. B. Simmons, E. Tillmanns, and R. X. Fischer, Am. Mineral., 69 (1984) 186. 18 M. Cal1igaris, G. Nardin and L. Randaccio, Zeolites 4 (1984) 251. M. Calligaris, A. Mezzetti, G. Nardin and L. Randacio, Zeolites 4 (1984) 323-328. M. Calllgaris, A. Mezzetti, G. Nardin and L. Randacio, Zeolites 5 (1984) 317-319. A. Alberti, E. Galli, G. Vezzalini, E. Passaglia and P. F. Zanazzi, Zeolites 2 (1982) 303-309. 19 D. W. Breck in 'Zeolite Molecular Sieves', Wiley and Sons (1973) p. 59. 20 D. P. Shoemaker, H. E. Robson and L. Broussard, ACS Adv. in Chem. Ser. 121 (1973) 106-118.
P.J. Grobet et al. (Editors) /Innovation in Zeolite Materials Science ElsevierSciencePublishers B.V.,Amsterdam- Printed in The Netherlands
THE
CRYSTAL
STRUCTURES OF SEVERAL MOLECULAR SIEVES
METAL
ALUMINOPHOSPHATE
J. M. BENNETT and B. K. MARCUS' Union Carbide Corporation, Tarrytown Technical Center, Tarrytown, New York, 10591. U. S. A.
ABSTRACT The crystal structures of CoAPO-44, CoAPSO-44, MAPSO-46, CoAPSO-47 and CoAPO-50 were determined from single crystal x-ray data. All five structures have the tetrahedral framework phosphorus or silicon alternating with the tetrahedral aluminum or the metal (cobalt or magnesium). The crystal structures of the 44's and 47 are topologically similar to the mineral chabazite, but with framework distortions which reduce the symmetry from rhombohedral to triclinic (P 1bar). The framework topologies of MAPSO-46 and CoAPO-50 are novel and form a new series of structures based on capped six membered rings with a unidimensional 12-ring channel system having a free aperature between 7A and 8A crossed-linked through 8 rings. CoAPO-50 is the end member of the series and is built from double four rings (a six ring capped top and bottom) only previously observed in Linde type A zeolite. Unlike the other metal aluminophosphate structures described here, the cobalt in CoAPO-50 occupies both the same crystallographic site as aluminum and a unique tetrahedral site. INTRODUCTION The aluminophosphate-based molecular sieves are an important new class of catalyst and 2
Included are families designated AlPO4-n
adsorbent materials I.
,
SAPO-n
3
,
MeAPO-n
4
,
MeAPSO-n I, etc., where -n denotes a specific structure type. The synthesis conditions involve crystallizing a gel between 100°C and 250°C in the presence of an organic template under hydrothermal conditions. The resulting solid may be calcined to remove both the template and water to allow the microporous nature of the material to be utilized. The crystal structures of a number of aluminophosphate-based molecular sieves and other I: I alumino phosphate structures have been reported including AlPO4-55, 7
8
9
10
11
12
AlPO4_11
6
,
13
AIPO4-12, GaPO4-14, AIPO4-15, AlPO4-16 , AlPO4-17 , AlPO4-21 , AIPO4-33 , 14 15. AIP0 and SAPO_34 The structures of the aluminophosphate molecular sieves show 4-EN3 four coordinated aluminum and phosphorus oxide frameworks with occasional secondary coordination of some of the framework aluminum with non-framework species such as H20 or OH occluded in the cavities.
Of recent interest are the
MeAPO and
MeAPSO families 1.4,
tv
-a
Table 1 Crystallographic and pertinent information for the reported structures.
0
gamma
U.C. Volume
Space Group
R%
Rw%
89.990
119.980
2459
P1bar
9.6
10.0
8474
2968
89.993
89.989
119.984
2466
P1bar
9.8
10.1
8433
2901
26.8922
90
90
120
4080
P3c1
9.0
11.9
6809
3926
13.8132
14.9937
89.997
90.081
120.066
2474
P1bar
10.0
11. 3
5129
2637
12.7485
12.7485
9.0147
90
90
120
1269
P3bar
8.2
7.1
868
849
13.384
13.384
90
90
90
2397
F23
Structure Type
a(A)
b(A)
c(A)
alpha
beta
CoAPO-44
13.6346
13.6299
15.2804
90.006
CoAPSO-44
13.6440
13.6430
15.2940
HAPSO-46
13.2251
13.2251
CoAPSO-47
13.8022
CoAPO-50 AlP04-16
13.384
Analysis Type
Crystal Color / Size / Shape
6(C6H11NH2)·Co4.SAl13.5P18072·qHZO
Typical
Blue Rhomb 90 microns along an edge
CoAPSO-44 5(C6H11NHZ)·KO.3Co2.5Al16.5P15.0Si3.007Z·qHZO
Bulk
Blue Rhomb 70 microns along an edge
Structure Type CoAPO-44
MAPSO-46
Composition
Number Reflections I>sigma )3sigma
8(C3H7)ZNH'Mg6Al22PZ6SiZ011Z'qH20
Typical
Colorless Lozenge 90 microns along an edge
CoAPSO-47 6(C3H7)ZNH·COZ.5~l15.ZP13.7Si4.6072·qH20
Bulk
Blue Rhomb 70 microns along an edge
CoAPO-50
Bulk
Blue trigonal rod 70 microns long
3(C3H7)ZNH'co3Al5P8032·6.7HZO
Note: Analysis type indicates the source of the analysis. Bulk is the bulk analysis of the sample. Typical is an analysis of a sample expected to have the same composition as that used for the structural study.
271
including the materials studied here which contain cobalt or magnesium, aluminum, phosphorus and sometimes silicon in the tetrahedral framework. These compositions can be considered in 3
terms of occupancy by the Co+2 or Mg+2 in the crystallographically equivalent Al+ site and a 4
5
similar occupancy by Si+ in a p+ site in a hypothetical I: I aluminophosphate framework resulting in a net negative framework charge for each cobalt,
magnesium or
silicon
incorporated. The framework charge must then be balanced by the charge on the non-framework components.
The cobalt containing materials are royal blue, similar in color to a cobalt
containing Akermanite 16 in which cobalt occupies a tetrahedral framework position. EXPERIMENTAL The x-ray powder diffraction patterns of CoAPO-44, CoAPSO-44 and CoAPSO-47 resemble that given by chabazite but with reflections that violate the Rbar3m rhombohedral symmetry.
Calcination yielded powder patterns that were more similar to the pattern of a
calcined chabazite.
Single crystal x-ray techniques showed that the symmetry was triclinic,
space group Plbar, if the pseudo-hexagonal settings were maintained to simplify testing the cause of the distortions from rhombohedral symmetry. The x-ray powder diffraction patterns of' MAPSO-46 and CoAPO-50 indicated that the materials were new topologies with no known zeolite analogues.
Table 1 lists the unit cell dimensions, space groups, compositions, and other
pertinent information for all five materials. The chemical analyses are either from the bulk sample when pure and containing large crystals or from a pure sample expected to have a composition similar to that from which the single crystals were chosen. Syntheses were from the corresponding metal (silico)aluminophosphate gels containing the appropriate amine as the template'". The CoAPSO-44 gel also contained K+ ions. The single crystal X-ray data were collected either on a Picker KRlSEL diffractometer or an Enraf Nonius CAD4 diffractometer using monochromatized copper K« radiation, and the structures were solved and refined using the SDP programs. The data were not corrected for absorption. Refinement of the 44's and 47 were begun using idealised parameters for chabazite but with strict alternation of aluminum and phosphorus in the framework and no assumptions as to the position of the cobalt even though the chemical analyses were consistent with the cobalt being in the framework. The final R factor in all three determinations was 9 to 11 % for the framework and template, exclusive of occuluded water molecules and template hydrogen atoms, confirming that they all have a chabazite-like topology but with triclinic symmetry. In all three structures,
272
TABLE 2 Refined parameters for the framework atoms of CoAPO-44 Atom' x y PI 0.98631 0.76732 P2 0.33579 0.43622 P3 0.34051 0.91253 P4 0.23875 0.23478 P5 0.56581 0.89689 P6 0.09565 0.44260 P7 0.77402 0.01210 P8 0.10741 0.67160 P9 0.56667 0.66302 All 0.99884 0.23420 A12 0.31985 0.43057 Al3 0.34694 0.90083 Al4 0.75954 0.76858 Al5 0.56749 0.89473 Al6 0.10251 0.43631 Al7 0.22873 -0.00328 Al8 0.09792 0.66879 Al9 0.55708 0.65570 011 1.00660 0.29998 014 0.88507 0.79575 016 0.96650 0.63774 0.86423 0.13013 017 022 0.33505 0.40308 024 0.67368 0.66730 026 0.77399 0.52815 029 0.44713 0.54177 033 0.64646 0.05523 0.54435 0.10330 035 035' 0.35852 0.00902 038 0.20966 0.76705 041 0.87135 0.73811 044 0.70795 0.70108 047 0.19697 0.08534 049 0.64134 0.65224 053 0.44251 0.91540 055 0.61102 0.92324 057 0.65838 0.98321 059 0.44672 0.23447 062 0.77896 0.55594 066 0.05796 0.39827 068 0.97896 0.35124 068' -0.14202 0.41625 071 0.08300 0.88664 073 0.32367 0.97632 074 0.25642 0.13242 077 0.26298 -0.01203 081 0.00201 0.30808 083 -0.24373 0.23058 086 0.11664 0.55333 088 1.06343 0.67597 092 0.57210 0.46160 092' 0.64494 0.65189 095 0.57727 0.79167 099 0.60719 0.66122 I
Z
0.89044 0.57064 0.77642 0.88647 0.57055 0.77382 0.89213 0.55808 0.76804 0.90190 0.76496 0.56966 0.91073 0.76326 0.56289 0.90148 0.76287 0.57160 0.01955 0.12338 0.15380 0.88062 0.65435 0.15345 0.22994 0.80151 0.32190 0.44317 0.49999 0.54338 0.87206 1.01391 0.11014 0.84173 0.80054 0.64845 0.83566 0.22339 0.45384 0.67634 0.50094 0.46100 0.87427 0.83842 0.86363 1.02484 0.18310 0.23496 0.79454 0.65970 0.44686 0.48226 0.55608 0.67892
Table 1: Al sites contain 25% cobalt.
TABLE 3 Refined parameters for the framework atoms of CoAPSO-44 B(A2 ) 1. 21 2.11 1.51 2.11 1. 21 1.71 1.71 1.72 1. 21 2.11 2.81 2.72 2.21 2.11 1.61 2.32 1. 81 1.61 2.07 2.63 2.74 2.74 3.15 4.25 4.46 2.64 2.30 3.59 4.66 3.15 3.75 5.17 3.35 2.64 3.65 2.44 3.85 2.84 2.20 1. 33 1. 93 3.45 1.53 2.30 2.04 5.66 4.36 3.95 2.94 2.64 2.44 3.95 2.03 2.14
X
0.99011 0.33477 0.34098 0.23040 0.57051 0.09720 0.77433 0.10151 0.56603 1.01091 0.33234 0.33700 0.76264 0.56177 0.09617 0.22865 0.09718 0.55703 1.01267 0.89068 0.97064 0.86441 0.35496 0.69196 0.77675 0.45500 0.65081 0.54697 0.33497 0.22123 0.87151 0.72281 0.19061 0.64222 0.54980 0.61327 0.66241 0.45050 0.77519 0.05803 0.98517 -0.12311 0.09077 0.32161 0.25612 0.72141 0.00200 -0.24511 0.11301 1.05244 0.56697 0.66272 0.58188 0.59333
Y
0.77264 0.43209 0.90853 0.23256 0.89900 0.44058 0.01092 0.66788 0.66436 1.23078 0.43257 0.90774 0.76530 0.89368 0.43997 0.00020 0.67037 0.65627 0.29458 0.80457 0.63715 0.12847 0.40854 0.66757 0.52802 0.54734 0.06123 0.10804 0.00185 0.77248 0.74318 0.69726 0.08002 0.65360 0.08804 0.92756 0.98773 0.23652 0.55545 0.39785 0.35412 0.43403 0.88725 0.97353 0.13116 0.99943 0.30620 0.22938 0.55152 0.66583 0.45636 0.66348 0.79105 0.65064
Z
0.89398 0.56568 0.77465 0.88759 0.56917 0.77272 0.89537 0.55467 0.76692 0.90576 0.77038 0.57153 0.90558 0.76614 0.56681 0.89960 0.76252 0.56860 0.01411 0.12605 0.15308 0.88500 0.65375 0.16267 0.23175 0.79984 0.32612 0.45029 0.49563 0.54424 0.88152 1.01434 0.11146 0.84398 0.20093 0.64874 0.84139 0.22861 0.45816 0.67112 0.50606 0.46301 0.87415 0.83231 0.85962 0.97606 0.18402 0.22370 0.79221 0.66184 0.43804 0.49625 0.55432 0.67474
B(A2 ) 2.02 2.32 2.21 3.22 1. 51 1.71 2.12 3.62 1. 51 2.92 1.62 1.82 2.02 2.82 2.12 2.62 1.62 2.52 1.25 2.25 1. 57 3.08 4.03 2.22 2.77 1.16 1. 37 2.01 2.09 3.33 3.07 5.62 2.40 2.37 3.43 2.20 1.38 2.37 1.82 1.03 1.72 2.69 1.23 1.44 2.77 5.75 4.56 3.70 1.7.0 1.96 3.56 2.29 1.97 1.82
Table 2: Al sites contain 13% cobalt. P sites contain 17% silicon.
273
there is no crystallographic evidence for the cobalt being anywhere but in the framework occupying an equivalent tetrahedral site with aluminum.
The aluminum/cobalt to oxygen
distances varied from 1.7..\ to 1.9..\ suggesting ordering; however no suitable ordering scheme could be developed even for CoAPO-44 which has the highest cobalt content corresponding to a uniform distribution of one cobalt and three aluminums around a phosphorus. In MAPSO-46 and CoAPO-SO, the framework topologies were initially determined by a combination of modeling and direct methods. In CoAPO-50 the cobalt was initially assumed to occupy the same crystallographic site as the aluminum.
However, the non-phosphorus
tetrahedral site along the threefold axes had four oxygen bond distances of 1.95..\ and was therefore redefined as cobalt, the remaining cobalt was randomly distributed in the same crystallographic site as the aluminum. The final x-ray framework composition C03AISP 8032 is consistent with the bulk chemical composition C03AIsP8°32' 3(C3H7)2NH' 6. 7H 0. RESULTS/DISCUSSION Chabazite-like Materials: The chabazite-type framework topology is a three dimensional arrangement of double six-rings linked together by four rings. The symmetry of chabazite is rhombohedral Rbar3m; however an ordered aluminosilicate mineral (Wilhendersonite
t
has triclinic symmetry, and
recent studies on several hydrated and dehydrated ion exchanged natural chabazites 18 have lower than rhombohedral symmetry. The reduction in symmetry is caused by distortion of the four membered rings. The partial occupancy of a tetrahedral site by cobalt might also be expected to distort the framework. analogue of chabazite (SAPO-34
15
)
The structure of a calcined silicoaluminophosphate
has rhombohedral symmetry suggesting that in this material
the inclusion of silicon into the tetrahedral framework does not distort the framework. Tables 2-4 show the refined parameters for CoAPO-44, CoAPSO-44, and CoAPSO-47. In the triclinic unit cell chosen, there are three chabazite cavities;
for both 44
materials, between one and two presumably protonated cyclohexylarnine molecules occupy either of two positions in each cavity (Figure I). The amino group has position disorder, such that the I, 3 and 5 positions are equally occupied by 1/3 of an amino group. The CoAPSO-44 structure has the potassium and cyclohexylamine molecules occupying similar positions in the cavities (Figure I), and both presumably balance the framework charge corresponding to the amount of cobalt and silicon in the structure. No attempt was made to determine the positions of the silicon in the tetrahedral framework, since it was felt that the cobalt sufficiently
274
Figure I. Part of a chabazite cage for both CoAPO-44 and CoAPSO-44 showing the upper of the two positions of the cyclohexylamine at the same height as three 4-rings in the chabazite cage. The lower cyclohexylamine. position is at the same height as the lower three 4-rings, which are only partially shown. The nitrogen atom of the amino group has positional disorder and points towards any of the three 8-rings. The position. in a chabazite cage, of the upper of the two potassiums in CoAPSO-44 is shown between the cyclohexylamine and the double six ring. The second potassium is in an equivalent lower position.
complicated the least squares refinement.
Both 44 structures contain water which was not
determined from these structural studies. The tetrahedral framework distortions of the 44's are similar, yet different from those of CoAPSO-47. The amounts of silicon and cobalt in the CoAPSO-44 and CoAPSO-47 are very similar while the two 44's differ greatly in the amounts of cobalt incorporated and only one(CoAPSO-44) has silicon incorporated. Since, in both 44 structures, the template molecule is the same and they occupy almost the same positions, which are different from those occupied by di-n-propylamine in CoAPSO-47, the suggestion must be made that the template or its position controls the framework distortions. In summary, these three 44 and 47 structures have a chabazite-like framework topology in which tetrahedral silicon and phosphorus randomly alternate with tetrahedral aluminum and cobalt, The upper limit to the amount of cobalt and silicon incorporated and the resulting maximum negative framework charge may be limited by the amount of positively charged species which can fit within the available void space.
There is sufficient space for two
cyclohexylamine rings to pack inside each chabazite cavity.
Since both potassium and
cyclohexylamine occupy similar locations in CoAPSO-44, the potassium is assumed to be equivalent to cyclohexylamine for the above argument.
The possible orientations for the
di-n-propylamine in the CoAPSO-47 are less well defined and, therefore, may not have the same maximum occupancy limit as the cyclohexylamines, but the equivalent (C + N) values for each template species suggest they should fill similar volumes in the channel system. The K+ in the CoAPSO-44 shows that the organic template is not the only species capable of balancing the net framework charge and neither rigorously defines the limiting value of the framework charge resulting from cobalt and silicon introduction.
275
CoAPO-50: Figure 2 is a stereo view of the CoAPO-50 topology showing the l2-rlng undimensional pore system and the interconnecting 8-rings lining the channel.
The structure can be
Figure 2. Stereo view oj CoAPO-50 topology down the c axis.
considered to be horizontal sheets of six rings held together vertically by tetrahedral atoms capping each six ring above and below it to form double four-rings. The number of vertical bonds holding the sheets together is small and may account for a lower thermal stability for this structure type as compared to most other aluminophosphate-based molecular sieve structure types.
Half of these vertical bonds are cobalt-oxygen-phosphorus bonds, the rest are
aluminum-oxygen-phosphorus bonds.
Figure 3 shows the excellent correspondence of the
calculated and observed powder patterns, and Table 5 shows the refined atom parameters.
~
/2
16
20
24 DEGREES 32 28
36
~
44
Figure 3. Calculated (a) and observed (b) powder patterns for CoAPO-50.
The observation that 66% of the cobalt occupies a special position in the structure, combined with the assumption that the remaining cobalt occupies the same crystallographic site as the aluminum requires that some of the four rings must contain two cobalt atoms, indirectly showing that cobalt-oxygen-phosphorus-oxygen-cobalt sequences are possible.
276 TABLE 4 Refined parameters for the framework atoms of CoAPSO-47 Atoml x 0.98911 PI P2 0.32683 P3 0.33246 P4 U.23897 P5 0.56096 P6 0.10606 P7 0.77613 P8 0.10921 P9 0.56451 All 1. 00124 A12 0.33172 Al3 0.34016 A14 0.77659 A15 0.56048 A16 0.10095 A17 0.23288 Al8 0.11556 Al9 0.55894 011 1.0221 014 0.8974 016 0.9795 017 0.8663 022 0.3437 024 0.7082 026 0.7701 029 0.4514 033 0.6633 035 0.5491 035' 0.3474 038 0.2178 041 0.8-752 044 0.7363 047 0.1957 049 0.6658 053 0.4391 055 0.6176 057 0.6865 059 0.4584 062 0.7891 066 0.0838 068 0.9954 068' -.1445 071 0.0937 073 0.3353 074 0.2468 077 0.2742 081 -.0163 083 -.2520 086 0.1144 088 1.0840 092 0.5775 092' 0.6462 095 0.5865 099 0.5885
y
0.76369 0.43838 0.89497 0.22828 0.89005 0.43993 1.00941 0.66954 0.66539 0.77212 0.43232 0.89509 0.78124 0.89314 0.45397 0.00105 0.67208 0.65829 1.2856 0.8102 0.6653 0.1187 0.3978 0.6905 0.5210 0.5414 0.0841 0.1203 0.0122 0.7767 0.7453 0.7277 0.0886 0.6724 0.8827 0.9331 0.9946 0.2365 0.5793 0.4255 0.3566 0.4136 0.8919 0.9917 1.1242 0.0026 0.2914 0.2271 0.5566 0.6648 0.4472 0.6418 0.7980 0.6451
TABLE 5 Refined parameters for the framework atoms of CoAPO-50
Z
B(A2 )
Atom!
0.89056 0.55599 0.77111 0.89212 0.55854 0.77469 0.89502 0.55405 0.77266 0.10399 0.76795 0.56808 0.89677 0.76965 0.56061 0.90512 0.77516 0.56518 1.0140 1.1339 1.1766 0.8610 0.6575 0.1848 0.2279 0.7836 0.3275 0.4603 0.5035 0.5231 0.8771 1.0103 0.1356 0.8258 0.8044 0.6559 0.8240 0.2074 0.4755 0.6750 0.5017 0.4430 0.8841 0.8399 0.8571 1.0147 0.1791 0.2121 0.8036 0.6607 0.4742 0.4933 0.5444 0.6772
1. 21 1.52 1.62 1.92 1.31 2.42 1. 31 1.62 1.92 1. 22 1.42 1. 22 2.42 1.92 1.52 1. 32 1.72 1.02 1. 38 1. 53 1.55 1.77 2.23 2.33 1. 21 1. 73 1. 31 2.17 1.39 1.92 1.28 2.89 3.45 3.15 1. 37 1.19 1.22 2.28 1.63 2.31 2.36 1.69 1.14 1.89 1.82 2.40 2.17 3.37 1.38 3.91 2.64 1. 35 1. 24 1. 74
PI P2 Col A12 03' 032 011 012 014 02
x 0.66666 0.32054 0.33333 0.85620 0.8599 0.3983 0.5442 0.1951 0.3333 0.3578
y
0.33333 0.85825 0.66666 0.32580 0.4419 0.2045 0.2286 0.5057 0.6666 0.9943
Z
0.18967 0.38432 0.18967 0.40070 0.5131 0.5240 0.2516 0.2326 0.9766 0.3518
B(A2 ) 1.81 1.72 2.25 1.98 1. 73 1. 21 1. 25 1.15 2.40 1.16
TABLE 6 Refined parameters for the framework atoms of MAPSO-46 Atom' x PI 0.66667 P2 0.19862 P3 0.46965 P4 0.20093 P5 0.46960 P6 0.00000 All 0.00000 Al2 0.46967 Al3 0.19875 Al4 0.46726 Al5 0.19352 Al6 0.66667 012 0.9846 016 0.0000 021 0.6875 022 0.7350 023' 0.9192 023 0.7826 032 0.1515 032' 0.1910 033 0.3389 034 0.1638 043 0.8976 044 0.3218 045 0.5189 045' 0.4884 054 0.1405 054' 0.1867 055 0.7279 056 0.9997 061 0.6666 065 0.7979
y
0.33333 0.18082 0.10767 0.96592 0.31962 0.00000 0.00000 0.31584 0.96524 0.11576 0.17290 0.33333 0.1174 0.0000 0.2336 0.0649 0.4727 0.2713 0.2587 0.0927 0.9936 0.2199 0.5052 0.0036 0.4365 0.2442 0.2616 0.0777 0.0750 0.8889 0.3333 0.4676
Z
0.06039 0.13165 0.19050 0.30722 0.36555 0.43771 0.06457 0.13168 0.18925 0.30775 0.36246 0.43950 0.5852 0.9957 0.0819 0.1160 0.1661 0.1759 0.1616 0.1748 0.1796 0.7555 0.7477 0.3158 0.3483 0.3316 0.3398 0.3187 0.3741 0.4222 0.0081 0.4151
B(A2 ) 1. 22 1. 62 1.02 1. 73 1.16 1.60 1.55 2.55 1.04 1.42 1.46 1.39 1.75 2.49 1.36 1.02 2.29 1.91 2.65 1.96 2.58 3.21 1. 74 1.95 1.15 2.85 1. 76 2.29 2.09 2.66 2.85 2.54
In Tables 2-6 the anisotropically refined tetrahedral atoms are given in the form of the isotropic equivalent displacement parameter.
, Table 4: AI sites contain 14% cobalt, P sites contain 25% silicon.
Table 5: AI site contains 17% cobalt.
277
Both 50 and 46 can be synthesised with di-n-propylarnine and the refinements show that the di-n-propylamine molecules occupy almost identical positions in the two structures: the nitrogen atom is centered in the 8-rings with the propyl groups radiating into the 12-ring channel. The configuration of the template was not sufficiently well refined to confirm the expected protonation of the amine to balance the expected framework charge. The 50 framework topology is an end member of a new series of hypothetical structures with MAPSO-46as another member. Prior to CoAPO-50, Linde Type A was the only molecular sieve structure built from double 4-rings (doubly capped 6-rings) but since has also been observed in AIPO4-1610. The 16 topology has been determined from synchrotron powder studies and consists of doubly capped 6-rings (double 4-rings) joined by single tetrahedra in a similar arrangement to that of a hypothetical tetrahedrally complete zunyite
l9
.
MAPSO-46: MAPSO-46 and CoAPO-50 are both built from capped six rings surrounding a large undimensional 12-ring channel. Figure 4 is a stereo view of the framework, showing the
Figure 4. Stereo view of MAPSO-46 topology down the c axis.
12-ring channels.
Figure 5 shows the relationship via a sigma transformation'" of the
six-ring in a double four-ring between the 50 and 46 framework topologies. Similar sigma expansions, adding single six rings, further increases the
c dimension giving rise to a
family of structures, all having a l2-ring pore opening interconnected through 8-rings. The sigma transformation of 50 to 46 may be the first such observation that does not result in the formation of a planar ring. The scattering factors for magnesium and silicon are similar enough to those of aluminum and phosphorous that the structure refined satisfactorily using the aluminum and phosphorous factors. By analogy with other studies and consistency with chemical analyses,
278
f5l;j
0fJ
(a)
~
(b)
(d)
(c)
Figure 5. Sigma transjormation of 50 into 46. (a) A representation of 50 showing the six-ring of the double four-ring involved in the sigma transformation. (b) Upper and lower segment of (a) produced by the sigma transformation. (c) Rotation of lower portion 60" necessary for bonding. (d) Final result showing unit present in the 46 topology.
the magnesium was assumed to occupy the same tetrahedral site as aluminum and the silicon as phosphorous. The final difference maps of MAPSO-46 and all other structures reported here, showed no tetrahedral position having a peak (positive or negative) larger than that given by an hydrogen atom.
Table 6 shows the refined atoms parameters. (b)
(a)
38
4
Figure 6 shows the
40
4
8
12
18
20
24
28 DEGREES 38 28
40
Figure 6. Calculated (a) and observed (b) powder patterns for MAPSO-46.
calculated and observed powder patterns; the differences in the two patterns are caused by incomplete modeling of the eight di-n-propylamine molecules since only six were located. CONCLUSIONS These five structure determinations yield conclusive evidence for the complete tetrahedral framework siting of the various metal atoms incorporated into the structures: aluminum, phosphorous, silicon, magnesium and cobalt. The sorption properties of -44 and -47 are similar to those expected for a chabazite topology. The sorption capacity of CoAPO-50 is
279
expected to be large, and the pore opening is similar in size, but not shape, to that of Linde Type X or Y. The 12-and 8-ring pore openings and large structural void volumes suggest that both -50 and -46 should have excellent sorption properties. The refinement and the chemical analyses of CoAPO-50 shows that the cobalt present in the framework replaces more than 1/4 of the aluminum present in a hypothetical I: 1 AJPO4 material. This means that some phosphorus atoms must have at least two cobalt atoms out of the 4 tetrahedral neighbors bonded to it through oxygens; futhermore, the structure must contain a significant number of four rings having only phosphorus and cobalt. The properties of such' an arrangement need to be studied. Thanks are given to J. J. Pluth, University of Chicago, for collecting the CoAPO-44 and CoAPSO-44 data, to L. M. King, W. C. Mercer, and L. D. Vail who synthesized and supplied the single crystals used in these studies, and to E. M. Flanigen, R. L.
Patton
and S. T. Wilson for their critical review of this manuscript. REFERENCES E. M. Flanigen, B. M. Lok, R. L. Patton and S. T. Wilson, Pure and Appi. Chern., 58 (1986) 1351-1358. 2 S. T. Wilson, B. M. Lok and E. M. Flanigen , U. S. Patent (1982) 4,310,440. S. T. Wilson, B. M. Lok, C. A. Messina, T. R. Cannan and E. M. Flanigen, J. Am. Chern. Soc.. 104 (1982) 1146-1147. 3 B. M. Lok, C. A. Messina, R. L. Patton, R. T. Gajek, T. R. Cannan and E. M. Flanigen, U.S. Patent (1984) 4,440,871. B. M. Lok, C. A. Messina, R. L. Patton, R. T. Gajek, T. R. Cannan and E. M. Flanigen, 4 S. T. Wilson and E. M. Flanigen, U.S. Patent (1986) 4,567,029. 5 J. M. Bennett, J. P. Cohen, E. M. Flanigen, J. J. Pluth, and J. V. Smith, ACS Symp. Ser. 218, (1983) 109-118. 6 J. M. Bennett, J. W. Richardson Jr., J. J. Pluth and J. V. Smith, Zeolites 7 (1987) 160-162. 7 J. B. Parise, J. Chern. Soc., Chern. Commun., (1984) 1449-1450. 8 J. B. Parise, J. Chern, Soc., Chern. Commun. (1985) 606-607. 9 J. B. Parise, Acta Crystallogr., C40 (1984) 1641-1642. J. J. Pluth, J. V. Smith, J. M. Bennett and J. P. Cohen, Acta Crystallogr., C40 (1984) 2008-2011 IO J. M. Bennett, Personal communication. 11 J. J. Pluth, J. V. Smith, and J. M. Bennett, Acta Crystallogr., C42 (1984) 283-286. 12 J. M. Bennett, J. P. Cohen, G. Artioli, J. J. Pluth and J. V. Smith, Inorg. Chem. 24 (1985) 188-193. J. B. Parise and C. S. Day, Acta Crystallogr., C41 (1985) 515-520. I3 P. R. Rudolf, C. Saldarriaga-Molina and A. Clearfield, J. Phys. Chern., 90 (1986) 6122-6125. 14 J. B. Parise in 'Zeolites' (Ed. B. Drzaj, S. Hocevar and S. Pejovnik) Elsevier, (1985) p. 271-278. 15 M. Ito, Y. Shimoyama, Y. Saito, Y. Tsurita, Y. and M. Otake, Acta Cryst., C41 (1985) 1698-1700 16 M. Kimata, Neuef. Yahrbuch Miner. Abh. 146 (1983) 221-241. 17 R. D. Peacor, P. J. Dunn, W. B. Simmons, E. Tillmanns, and R. X. Fischer, Am. Mineral., 69 (1984) 186. 18 M. Cal1igaris, G. Nardin and L. Randaccio, Zeolites 4 (1984) 251. M. Calligaris, A. Mezzetti, G. Nardin and L. Randacio, Zeolites 4 (1984) 323-328. M. Calllgaris, A. Mezzetti, G. Nardin and L. Randacio, Zeolites 5 (1984) 317-319. A. Alberti, E. Galli, G. Vezzalini, E. Passaglia and P. F. Zanazzi, Zeolites 2 (1982) 303-309. 19 D. W. Breck in 'Zeolite Molecular Sieves', Wiley and Sons (1973) p. 59. 20 D. P. Shoemaker, H. E. Robson and L. Broussard, ACS Adv. in Chem. Ser. 121 (1973) 106-118.