Trigonal Prismatic or Octahedral Surrounding in Sheet Oxides?

Abstract

According to the oxygen packing two types of alkali ion surroundings (octahedral or trigonal prismatic) are possible in the AXMO2sheet oxides or the related A2MO3 compounds. The stability of both environments is discussed from the geometrical and electrostatic view points. Structural transitions to metastable forms can be induced by high pressure, intercalation, desintercalation or exchange reactions. The possibility of room temperature transformations can be anticipated from the relationships between the various oxygen packings. © 1981, Walter de Gruyter. All rights reserved.