Location of cations in synthetic zeolites–X and –Y. Part 6.—Influence of X-ray irradiation on the location of exchangeable cations

Abstract

The X-ray irradiation of a series of Ca– and La–Y zeolites, pretreated at different temperatures results in the formation of oxides (CaO and La₂O₃) in the sodalite cage, and in a depopulation of the hexagonal prisms. The structures are similar for all (previously different) samples and cannot be distinguished statistically. The number of oxygens in the oxides largely exceeds the level of residual water and originates from the framework. The reversible mobility of the framework oxygens is postulated, considering the zeolite framework and cations merely as a “mixed oxide”.