Zeolites are materials with widespread applications. A newly synthesized example has desirably large pores, as well as the virtue of thermal stability, and shows the value of structure-prediction programs. A microporous crystalline silicate with exceptionally large pores and great potential as an industrial catalyst is described on page 842 of this issue. This zeolite is dubbed ITQ-33, and has been discovered by Avelino Corma and co-workers in Valencia. Zeolites are crystalline oxide materials with atetrahedral framework structure that contains cavities in which guest' molecules can move relatively freely. Such molecules can rapidly be adsorbed, react and desorb, making zeolites particularly useful for catalytic and separation applications. The framework is composed mainly of silica tetrahedra, but many other elements, such as aluminium, titanium or germanium, can be incorporated into the framework structure. Aluminium is particularly valuable in catalysis - if substituted for silicon, it makes the framework anionic, so requiring the presence of readily available cations for interaction with the adsorbed species; if the cation is a proton, the material becomes a strong, solid acid.
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