Ein weiteres Gemischtvalentes Oxoniobat: Sr5Nb34+Nb25+O16

About a Mixed Valence Oxoniobate: Sr₅Nb₃⁴⁺Nb₂⁵⁺O₁₆ The hitherto unknown compound Sr₅Nb₅O₁₆ was prepared and examined by X-ray single crystal work. It crystallizes with orthorhombic symmetry (space group D–Pmn2₁, a = 3.992(1), b = 32.476(10), c = 5.677(2) Å; Z = 2). Sr₅Nb₅O₁₆ consists of stacked perovskite-like blocks cut by a plane perpendicular to the cube face diagonal of the perovskite structure. The coordination relations of the intersections between those blocks and the distribution of Nb⁵⁺ and Nb⁴⁺ are discussed.