Characterization of a New Microporous Lithozincosilicate with ANA Topology

Abstract

A new microporous lithozincosilicate (Cs12Li13[Li3Zn8Si37O96]·4H2O), an analogue of pollucite (CsAlSi2O6) and analcime (NaAlSi2O6), contains lithium in both framework and nonframework sites. This represents the first example of the incorporation of lithium into the ANA framework structure type. The analysis of the crystal structure used X-ray and neutron powder diffraction techniques, which reveal partially ordered sites in the framework occupied by Li, Zn, and Si atoms. The framework sites are occupied in a manner to distribute the low valent cations as far apart as possible. The pore system of the material consists of large cuboctahedra, occupied by Cs and water molecules, and smaller vacancies available for siting of nonframework Li bounded by six- and eight-membered rings of framework tetrahedra.