Bi3ScMo2O12:: the difference from Bi3FeMo2O12

Bi3ScMo2O12, tribismuth(III) scandium molybdate(VI), has a framework structure derived from that of scheelite. It is nearly isotypic with Bi3FeMo2O12; while in the latter the Fe-III atom is tetrahedrally coordinated by O atoms, the Sc atom in the title compound has a distorted octahedral coordination, and is substituted by Bi to a very minor extent (ca 4%). The change in coordination is achieved predominantly by shifts of two O atoms. The average Sc-O and Mo-O bond lengths are 2.162 and 1.775 Angstrom, respectively. The environments of the two eight-coordinated Bi sites are very similar to those in Bi3FeMo2O12. All atoms are on general positions except Sc and one Bi (both of which have site symmetry 2).