Zeolites and zeolite-like materials

Abstract

Zeolite structural chemistry is no longer confined to porous aluminosilicates. The wide range of zeolite-type framework structures is outlined following a generalized formula for zeolitic materials. These include interrupted networks with terminal hydroxyl groups, anionic frameworks containing hydroxo bridges and other derivatives of tetrahedral framework structures, besides novel topologies. The diversity of structures is further enhanced by inherent and frequently observed faults. Crystalline molecular polysiloxane and related compounds are of considerable interest in connection with the formation of polymeric networks of zeolites and zeolite-like materials. Configurations comprising a maximum of smallest possible rings are a prerequisite for creating very open networks. Observed structures containing combinations of 3- and 4-rings are of particular interest in this respect. Model considerations on this basis indicate that future syntheses of zeolitic materials of very low framework density should be feasible. © 1986 IUPAC