Stoichiometry and doping mechanism of the cubic pyrochlore phase in the system Bi2O3-ZnO-Nb2O5

Abstract

The subsolidus phase diagram of the system Bi2O 3-ZnO-Nb2O5 in the region of the cubic pyrochlore phase has been determined at 950 °C. This phase forms a solid solution area that does not include the so-called ideal composition P, Bi 3Zn2Nb3O14. It may be described in terms of two compositional variables: ZnO deficiency compared to P together with variable Bi : Nb ratio. Density measurements, preliminary crystallographic studies and the phase diagram indicate the solid solutions to have general formula, Bi3+yZn2-xNb3-yO14-x-y.: -0.11(1) ≤ y ≤ 0.14(1) and -0.03(1) ≤ x ≤ 0.31(1). © The Royal Society of Chemistry 2005.