HIGH-RESOLUTION NEUTRON POWDER DIFFRACTION STUDIES OF THE STRUCTURE OF CSDSO4

High-resolution neutron powder diffraction data were used to determine the crystal structure of the superionic conductor CsDSO4 at 300 K (low-conductivity phase) and at 448 K (superionic phase). A full structural analysis was performed, using the Rietveld method, to obtain previously unknown atomic positions, site occupancies and temperature factors for the light atoms. The mechanism of deuterium diffusion is discussed. At 300 K: monoclinic, P2(1)/c, a = 7.78013 (9), b = 8.13916 (2), c = 7.72187 (9) angstrom, beta = 110.8720 (4)-degrees, R(wp) = 4.19% for 7331 profile points (844 reflections). At 448 K: tetragonal, I4(1)/amd, a = 5.74147 (9), c = 14.31508 (26) angstrom, R(wp) = 2.21% for 8289 profile points (194 reflections).