A new antimony(III) molybdate with a layer structure: KSbMo₂O₈

The crystal structure of KSbMo₂O₈ was determined from single-crystal X-ray diffraction data. It crystallizes in the triclinic space group P1 with a = 5.015(2), b = 7.4216(6), c = 10.304(1) Å; α = 90.45(1), β = 100.29(2), γ = 107.79(1)°; V = 358.5 ų, Z = 2, R = 0.028, R_w = 0.038 for 1590 unique reflections with I > 2.5 σ(I). The structure contains layers of antimony molybdate with the potassium cations between the layers. Each layer is built up from strongly distorted MoO₆, MoO₅, and SbO₆ polyhedra and consists of two types of chains parallel to the a-axis. Sb₂O₁₀ dimers, formed by two edge-sharing SbO₆ polyhedra, are connected by MoO₅ groups to form chains. The other type of chains is constructed from skew edge-shared MoO₆ octahedra, which are linked through Sb₂O₁₀ dimers such that layers in the (010) plane are formed. Each K⁺ cation is coordinated by nine oxygen atoms in a geometry of tricapped trigonal prism.