Crystal structure, spectroscopy, and thermal expansion of compounds in MI2O–Al2O3–TiO2 system

Compounds that crystallize in four structure types in M2O–Al2O3–TiO2 systems have been prepared by solid-phase reactions. LiAlTiO4, K2Al2Ti6O16, Rb2Al2Ti6O16 and Cs2Al2Ti6O16 were synthesized for the first time. Their crystal structures were refined using the Rietveld method. Crystal–chemical systematics was performed for all compounds in M2O–Al2O3–TiO2 system. Raman and IR investigation have been also made. Thermal expansion coefficients of compounds with the compositions MIAlTiO4 (MI–Li, Cs) and MI2Al2Ti6O16 (MI–Na, K, Rb, Cs) were determined with the use of high-temperature X-ray diffraction analysis.