Synthesis and crystallochemical characterization of the Tb1-xBixSrO3 type solid solution

Solid solution of the Tb1-xBixSrO3 type was investigated under oxidizing sintering conditions. The domain of homogeneity was determined to be within the range 0 less than or equal to x less than or equal to 0.33. Variations of lattice parameters as well as sample densities vs. the substitution parameter x are given. The effective valency of Bi and Tb ions, (V) over bar((Tb,Bi)), remains invariant and is close to +4 through the whole domain of homogeneity. The present data do not permit the exact variation of valencies of Bi and Tb ions to be separately recognized. However, the solubility limit found directly indicates a nearly +5 valency of Bi ions and a variable valency of Tb ions, the latter decreasing vs. x to the level of +3.5 characteristic for Tb4O7-the most stable terbium oxide in air. The possibility of a successful synthesis of the hypothetical Tb+3Bi+5Sr2O6 is explored. (C) 1996 Academic Press, Inc.