The substitution of vanadium by chromium in thallium pentavanadium octasulfide. Part 1: Anisotropic metal atom interactions. A single crystal X-ray study

Abstract

Single crystal X-ray investigations of the series TIV 5−yCr yS 8 (0≤y≤5) give evidence that anisotropic metal metal atom interactions are responsible for the unsusual increase of the unit cell volume when V is substituted by Cr. Furthermore, the change of the lattice parameters exhibits appreciable deviations from linearity as a function of increasing Cr content. This behaviour can be attributed to the anisotropic metal atom interactions. The volume of the nearly rectangular channels which accomodate the Tl atoms is mostly affected by the increased unit cell volume. The analysis of the anisotropic displacement parameters (ADP) of the Tl atoms reveals that the kind of static disorder of Tl changes with increasing Cr-content.