Structural studies on A-cation-deficient perovskite-related phases. II

Electron diffraction/microscopy and X-ray diffraction techniques have been used to study the thorium/vacancy ordering and microdomain structures of quenched and slow-cooled samples of the A-cation-deficient perovskite-related phase ThNb4O12. In both types of samples, there is primary ordering of thorium atoms into the cuboctahedral sites in alternate (001)sub(p) layers. The quenched and slow-cooled samples have different secondary orderings of thorium atoms and vacancies in the occupied (001)sub(p) layers. Optical transform methods were used to check the validity of microdomain models for both the quenched and the slow-cooled samples. (Auth.)