Crystal growth and structure of a new manganese vanado-antimonate MnVSbO 6

Abstract

Single crystals of a new compound of formula MnVSbO 6 were grown by slow cooling from a V 2O 5–B 2O3 3 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-PbO 2 type with a cation ordering similar to that found in Fe 2WO 6. Cations occupy octahedral sites in the PbO 2-like layers. Zigzag chains of edge-sharing MnO 6 octahedra alternate with mixed Sb/V chains following a –Mn–Sb/V–Sb/V– sequence. The magnetic susceptibility of MnVSbO 6 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 Mn 2+V 5+Sb 5+O 6.