“…Numerous attempts have been reported to improve the ion conductivity by isovalent and aliovalent substitution of the transition metal and of bismuth. The Bi-P(V)-O system (1)(2)(3)(4) and the pseudoternary systems Bi O -PbO-M O , where M" P, V, As, have been extensively investigated (5)(6)(7) in the expectation that some of the compounds will display interesting physical properties such as improved anionic conduction. Mizrahi et al (5) described new phases with M"V and, in particular, Pb BiVO .…”