Crystal growth and structure of a new manganese vanado-antimonate MnVSbO6

Single crystals of a new compound of formula MnVSbO₆ were grown by slow cooling from a V₂O₅-B₂O3₃ flux at 900°C. The compound crystallizes in the orthorhombic space group Pbcn (No. 60), with cell parameters (in the Pcnb setting) a=4.6604(3) Å, b=4.9603(3) Å, c=17.1433(9)Å, Z=4. The crystal structure was solved from 1188 independent reflections to R_w=3.20% and goodness-of-fit 1.5 for 44 refined parameters. The structure can be described as a superstructure of the α-PbO₂ type with a cation ordering similar to that found in Fe₂WO₆. Cations occupy octahedral sites in the PbO₂-like layers. Zigzag chains of edge-sharing MnO₆ octahedra alternate with mixed Sb/V chains following a -Mn-Sb/V-Sb/V- sequence. The magnetic susceptibility of MnVSbO₆ follows the Curie-Weiss law down to ca. 15 K, where it orders antiferromagnetically. The bond lengths and Curie constant are consistent with the expected charge distribution Mn²⁺V⁵⁺Sb⁵⁺O₆.