A study of the cation order in hollandite-like M xT 5S 8 phases

Abstract

The phases InTi 5S 8, InCr 5S 8, Ba 0.50V 5S 8, Ba 0.50V 5S 8, Ba 0.51Cr 5S 8, Ba 0.56Cr 5S 8 and Sr 0.48Cr 5S 8 were prepared and their crystal structures determined from single crystal data and diffuse scattering. Their basic structure is isotypic to the TIV 5S 8 type with space group C2 m . Indium is in a split position resulting in an asymmetric four-fold coordination. In the Ba x T 5S 8 phases the barium ions form one-dimensional domain structures ( x ≈ 0.56) with a nine-fold superperiod along the b axis, or two-dimensional sheets ( x ≈ 0.5) with mesh (2 b, c). Strontium forms a three-dimensional superstructure.