Novel Polyoxovanadate K₂ZnV₅O₁₄: Crystal Structure and Peculiarities of Crystal Chemistry

A novel structure type has been established as a result of studying a non-merohedral microtwin of polyoxovanadate (K₂ZnV₅O₁₄) by X-ray diffractometry (R = 0.0595). The new compound, synthesized under hydrothermal conditions in the ZnCl₂–K₂CO₃–V₂O₅–H₂O system, is characterized as follows: a = 8.066(5) Å, b = 8.117(5) Å, c = 9.236(5) Å, β = 105.287(5)°, sp. P2₁/m, Z = 2, ρ_calcd = 3.54 g/cm³. Edge-shared five-core "clusters" consisting of vanadium octahedra, between which ZnO₄ tetrahedra (sharing vertices with octahedra) are located, form two-dimensional two-layer anion packets of the (ZnV₅O₁₄)^2– composition, alternating along the c axis with layers of potassium atoms. Structural peculiarities determine the morphology and color of new-phase crystals.