Ionic conductivity of potassium antimonate tungstates with partial Na+ or Li+ substitution for K+

We have studied the formation of monovalent metal antimonate tungstates by solid-state reactions in the xM(2)CO(3) center dot (y - x)K2CO3 center dot ySb(2)O(3) center dot 2(2 - y)WO3 (M = Na, Li; 0 a parts per thousand currency sign x a parts per thousand currency sign y; 1.0 a parts per thousand currency sign y a parts per thousand currency sign 2.0) systems and identified the stability regions of pyrochlore phases at a temperature of 1123 K in the KSbO3-WO3-MSbO3 (M = Na, Li) composition triangles. A model has been proposed for the ion distribution over the sites of the pyrochlore structure (sp. gr. Fd3m). The conductivity of the monovalent metal antimonate tungstates has been measured in the temperature range 500-1000 K, and a relationship between their ionic conductivity and structure has been established.