Preparation and properties of reduced bismuth and antimony molybdenum oxides.

Reduced ternary molybdenum oxides, particularly those containing an alkali metal as the ternary element, exhibit a wealth of structural complexity and a variety of physical phenomena including charge-density waves and superconductivity. We are interested in phases related to the alkali molybdenum oxide bronzes but containing other ternary elements. From molybdenum trioxide- rich, low-melting eutectics formed in the MoO(3)-Bi(2)O(3) and MoO(3)-Sb(2)O(3) systems, large crystals of two new reduced bismuth molybdenum oxides and one antimony molybdenum oxide have been grown by the electrolytic reduction of molten salts. These phases are purple with high reflectivity, and show semiconducting behavior. All are orthorhombic with the same systematic absences (corresponding to space groups P(mma) or P(mc2-1). Empirical formulas of these new oxides have the form M'(x)Mo(2)O(5), with x=0.22 or 0.27 dependent on growth conditions for the bismuth-containing compounds and with x=0.47 for the antimony- containing phase.