Powder X-ray diffraction study of the rhombohedral to cubic phase transition in TiF3

Abstract Synchrotron powder diffraction has been used to examine the crystal structure of the TiF3 between 20 and 450 K with emphasis on the cubic to rhombohedral structural phase transition near 370 K. This transition involves an apparently continuous reduction in the tilts of the TiF6 octahedra. A remarkable difference in the thermal expansion coefficients in the two phases is observed.