Avoiding Distortions

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Science  12 Aug 2005:
Vol. 309, Issue 5737, pp. 990
DOI: 10.1126/science.309.5737.990c

The formation of silica zeolites usually requires some structural distortion, but what has been observed experimentally is that the bending within the SiO4 tetrahedra is minor and occurs mainly along the bonds connecting them. Zwijnenburg et al. performed a computational study of known zeolitic frameworks, as well as hypothetical frameworks built up of three-connected polyhedral tiles (simple tilings such as double 4-rings), whose packing can be used to represent known frameworks. They found that the experimental frameworks had minimal tetrahedral distortion (less than 2.5 × 10−2 Å2), but that hypothetical frameworks, even ones with enthalpies similar to those of experimental frameworks, had an order of magnitude or more tetrahedral distortion. They conclude that although a few of the hypothetical frameworks may be realizable, most of the more distorted ones will likely elude hydrothermal synthesis. — PDS

J. Phys. Chem. B 10.1021/jp0531309 (2005).

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