SODIUM-BISMUTH-TITANIUM-TUNGSTEN OXIDE HAVING INDEFINITE-RATIO PYROCHLORE-TYPE STRUCTURE OF CUBIC SYSTEM AND PRODUCTION THEREOF

摘要

PURPOSE:To provide a sodium.bismuth.titanium.tungsten oxide having a specific composition and expected to be useful as an ion-conductive material. CONSTITUTION:A sodium.bismuth.titanium.tungsten oxide having indefinite-ratio pyrochlore-type structure of cubic system and expressed by general formula Na2xBi2yTizOx+3y+2z+3u (x=0.037-0.047; y=0.247-0.260; z=0.632-0.653; u=0.055-0.070; x+y+z+u=1). The oxide can be produced by the following method. (A) Na2CO3 or a compound decomposable to Na2O by heating, (B) Bi2O3 or a compound decomposable to Bi2O3 by heating, (C) TiO2 or a compound decomposable to TiO2 by heating and (D) WO3 or a compound decomposable to WO3 by heating are mixed together in a manner to give a composition containing 3.7-4.7mol% Na2CO3, 24.7-26.0mol% Bi2O3, 63.2-65.3mol% TiO2 and 5.5-7.0mol% WO3 and the mixture is heated at about 900 deg.C in air.