Theoretical Studies on Zeolite Composition and Loewenstein’s Rule

Abstract

Synthetic zeolites play an important role in catalysis and, in particular, they are widely used in the petroleum industry. Zeolites are alumosilicate frameworks with a well defined geometrical structure consisting of systems of channels and cavities up to 10Å in diameter. Figure 1 shows the structural arrangement of faujasite type zeolites, the synthetic forms X and Y of which are among the most frequently used zeolite catalysts (1). Each vertex in Figure 1 represents a tetrahedrally coordinated centre occupied by a silicon or aluminum atom, while each edge represents an oxygen bridge between two tetrahedral centres. The Roman numbers indicate the possible positions of charge compensating cations.