Preparation of trigonal and hexagonal cuprous chromite and phase transition study based on single crystal structure data

Single crystals of trigonal 3R-CuCrO2 were grown by a flux decomposition method. A new metastable hexagonal phase of 2H-CuCrO2 was prepared by quenching the trigonal crystals from 1100 degrees C to room temperature. A model of the atom shifts occurring during the 3R-2H structural phase transition is presented. During the transformation parts of the layered structure do not change. In other regions atom displacements up to 1.72(1) Angstrom occur. The phase transition unites a first-coordination reconstructive transformation and a second-coordination distortional transformation. (C) 1996 Academic Press, Inc.