Potassium Molybdenum Oxide ‘Bronzes’

Abstract

Wold, Kunnmann, Arnott and Ferretti¹ recently reported the first successful synthesis of molybdenum ‘bronzes’. These inert, opaque and highly coloured phases are ternary non-stoichiometric oxides containing fractional quantities of alkali metal atoms, and like other known members of this class of solid possess some of the electrical characteristics of metals. Two potassium bronzes, red K_0.26MoO₃ and blue K_0.28MoO₃, were both prepared by the electrolysis of fused salt mixtures of K₂MoO₄ and MoO₃ under slightly differing conditions, the first being a typical semi-conductor while the second behaved as a metal.