Synthesis and crystal structure of a new antimony(III) molybdate: LiSbMo₂O₈

A new antimony(III) molybdate, LiSbMo₂O₈, was synthesized and its crystal structure was determined from single-crystal X-ray diffraction data. It crystallizes in the monoclinic space group C2 c (No. 15) with a = 21.640(6), b = 4.9305(7), c = 5.5448(6) Å, β = 100.35(1)°, V = 582.0(2) ų, Z = 4, and R = 0.026. The structure consists of corrugated perovskite-like layers of markedly distorted MoO₆ octahedra with the Sb³⁺ and Li⁺ ions segregated on opposite sides of each layer. The Sb³⁺ ion shows one-sided 4-coordination with four more oxygen atoms lying on the other side of the Sb³⁺ ion at considerably longer distances. The coordination around the Li⁺ ion is octahedral. Alternatively, the structure is described as consisting of rutile-type slabs three edge-sharing octahedra thick, which are connected by the Sb³⁺ ions to form a three-dimensional framework. SCHLEGEL diagrams are used to help describe the arrangement of the next-nearest neighbors of the coordination polyhedra of Mo and Li. The structure is closely related to those of SbNbO₄, α-, and β-Sb₂O₄.