Syntheses and crystal structures of new ReO₃-type-derived transition metal oxide fluorides

Mixed-metal oxide fluorides MNb₂O₃F₆ (M = Mg, Zn), MgM₂OF₈ (M = Ti, Zr), Fe₂TiO₈F, and TiNb₂O₅F₄ were prepared by treatment of their corresponding oxides with a 1:1 mixture of hydrofluoric acid and HNO₃. Crystal structures were investigated by means of X-ray powder diffraction. The anion distribution of MgZr₂OF₈ was studied theoretically. MNb₂O₃F₆-type compounds can be structurally refined in the cubic ReO₃ type, MgTi₂OF₈,and MgZr₂OF₈ in the cubic NaSbF₆ type, Fe₂TiOF₈ in the rhombohedral VF₃ type. All presented oxide fluorides are colorless powders and the metal ions are in the highest formal valence state. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)