9627222 Hughes This study will characterize the nature of chemical substitutions by precise diffraction data. The project involves three tasks: incorporation of REE in titanite, high-precision single crystal and Rietveld studies of LaNi5-ySny hydrides, and REE in naturally-occurring perovskite phases. Of particular interest in titanite is the accommodation of REE's and the concomitant charge-balancing substitution for the Ca+2 ( REE+3 exchange. Intermetallic compounds such as LaNi5 doped with varying amounts of Sn, are under intense multi-disciplinary investigation for use as hybrid hosts for H fuels and electrodes in high-performance batteries. High-precision crystal structure studies investigate the disorder in the phase as SN substitutes for Ni. Rietveld analysis of the atomic arrangements will be undertaken to overcome the pervasive twinning in perovskites that mitigates against solution/refinement by single crystal methods.
