Crystallization of montesommaite-type aluminosilicate by post-synthetic treatment of lithosite-type aluminosilicate

Abstract Montesommaite-type aluminosilicate was synthesized for the first time by the steaming of lithosite-type aluminosilicate which had been previously synthesized under solvothermal conditions. The montesommaite-type aluminosilicate samples obtained were pseudomorphs of the lithosite-type crystals and euhedral octahedral particles. Owing to the structural similarity, the montesommaite-type crystal could be grown hetero-epitaxially on the lithosite-type one. In addition, the montesommaite-type zeolite was predominantly crystallized at temperatures higher than 150 °C. The optimum duration of steaming for obtaining a single phase of montesommaite-type aluminosilicate changed with both the steaming temperature and initial K/Si ratio in the initial lithosite-type aluminosilicate. Since the lattice parameter of lithosite-type aluminosilicate sample changed with potassium content, which gradually changed with steaming, it was suggested that the steaming treatment caused the crystallization of montesommaite-phase not only by the destruction of the lithosite-type crystal, but also by changing the lattice parameter of the –LIT structure as the substrate.