ZIRCONOLITE CAZR0.92TI2.08O7 FROM 294-K TO 1173-K

High-resolution neutron powder diffraction data were collected from the monoclinic zirconolite CaZr0.92Ti2.08O7 at temperatures from 294 to 1173 K. The structural parameters of this compound, which were derived by Rietveld refinement, are not substantially affected by temperature. The lattice parameters increase with temperature and the expansion is essentially isotropic. With the possible exception of the Ti(1)O6 octahedron, which has more or less the same size over the complete temperature range, all the oxygen polyhedra expand more or less uniformly with temperature. The weighted mean thermal parameter fits a Debye function with θm=535±20 K superimposed onto a temperature independent term with an RMS displacement of 0.27 Å2 arising from static disorder. © 1992 Academic Press, Inc.