Bi_1.7V₈O₁₆: The First Bi-Hollandite-Type Compound

Abstract

Bi_1.7V₈O₁₆ was synthesized by high temperature solid state reaction between Bi₂O₃, V₂O₅, and V₂O₃. The compound crystallizes with tetragonal symmetry, space group I4/m. The structure refinement using single crystal data confirms that the compound belongs to the hollandite family. It is the first hollandite-type compound containing bismuth in the large tunnels of the V₈O₁₆ framework. The bismuth atom forms a very flat BiO₄ square pyramid with the skeleton oxygen atoms. Bi_1.7V₈O₁₆ is oxidized to BiVO₄ and V₂O₅ at 400°C in air, as evidenced by TGA and DSC.