Structural investigations on bismuth-based mixed oxides
Abstract The structures of the low-temperature modification of the rhombohedral solid solutions Bi 1−x M x O 1.5 x 2 with M=Ca, Sr or Ba ( x =0.130, 0.235 and 0.156 respectively) have been solved by means of Fourier syntheses and least-squares refinement. Layers of cations are stacked along the c axis, with the following sequence … BiBi(M, Bi)BiBi(M, Bi)…. Two kinds of oxide ions were detected inside the blocks consisting of a mixed layer surrounded by two Bi layers. The conduction properties can be ascribed to the migration of the remaining anions in the space between two successive Bi layers.