Zeolites are crystalline aluminosilicates with regular arrays of pores or channels, whose sizes correspond to dimensions of small molecules (a few Angstroms). They contain exchangeble ions and can be highly hydrophilic. With these properties, zeolites are used commercially as molecular sieves, as ion exchangers in detergents and water softeners, catalysts in the petroleum industry, as dessicators to dry solvents or foods and for a range of other applications. Because of their uniform cages, zeolites are suitable hosts to trap and confine functional molecules that can provide the host-guest structure with novel electronic, magnetic, and optical properties. Sodalites are a sub-class of zeolites with small, close-packed cages. We have employed sodalites as host structures for small clusters. With one particular composition, silver-oxalato sodalites, reversible changes in optical properties were possible, allowing the possibility for high density information storage.
