Synthesis and phase composition of NaxMxTi8-xO16(0.67≤x≤2.0; M = Al, Ga, In)

Abstract

The phase composition of Na x M x Ti8 – x O16(M = Al, Ga, In) materials was studied by x-ray diffraction. In the Al system, a hollandite phase was obtained in the composition range 0.67 ≤ x≤ 2.0. The results are interpreted in terms of Goldschmidt's tolerance factor. It is shown that A2B8O16compounds with the hollandite or Na x TiO2-type structure are more difficult to prepare at smaller ionic radii of M. The assumption is made that the monoclinic Na x TiO2-type phase may, under certain conditions, have a channel structure.