The crystal structure of non-stoichiometric monoclinic Cr5+ x S8 (x = 0.20 and 0.26) prepared under high pressure and high temperature

Abstract Two non-stoichiometric chromium rich Cr 5+ x S 8 ( x = 0.20 and 0.26) samples were prepared under high pressure and high temperature conditions. In the crystal structures three different metal atom sites are fully and the fourth site is only partially occupied. The results of single crystal and Rietveld refinements are in good agreement. The CrS 6 octahedra share common corners and common faces. Across common faces extraordinary short Cr—Cr distances are observed suggesting metal-to-metal bonding. On the basis of the distortion of the CrS 6 octahedra Cr 4+ is located on two of the four Cr sites. With increasing Cr content the amount of Cr 4+ is lowered and the distortion of two of the four CrS 6 octahedra is significantly reduced.