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

• Montesommaite-type aluminosilicate (synMON) was synthesized for the first time.
• The synMON was obtained by steaming of as-synthesized lithosite-type aluminosilicate (synLIT).
• The synMON crystals could be grown hetero-epitaxially on the synLIT crystal.
• The optimum duration of steaming changed with both the steaming temperature and initial K/Si ratio in the synLIT.
• By steaming, the size of c-axis in synLIT could be adjusted as the substrate for the hetero-epitaxial growth of synMON.

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.

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