Synthesis and structure of some interesting oxides of bismuth

Abstract

Synthesis and structures of several new oxides containing bismuth are described. Three types of structures are common among the multinary oxides containing trivalent bismuth. They are the sillenite structure of γ -Bi²O³, the layered perovskite structure of Aurivillius phases and the pyrochlore structure. The influence of Bi³⁺:6s² lone pair electrons is seen in all the three structures. In transition metal oxides containing trivalent bismuth,d o cations (Ti⁴⁺, Nb⁵⁺, W⁶⁺) stabilize the layered perovskite structure, while cations containing partially-filledd orbitals (V⁴⁺, Cr³⁺, Fe³⁺) favour pyrochlore-related structures. Ferroelectric distortion of MO₆ octahedra of thed ^o cations seems to play an important role in stabilizing layered perovskite structures.