THE CRYSTAL-STRUCTURE OF TI3PD2.4

The crystal structure of the deuteride phase of Ti3P has been refined from neutron powder diffraction data taken at 25 degrees C and 250 deg rees C using the Rietveld method. The tetragonal beta-V3S-type structu re, space group P4(2)/nbc, involves three crystallographically indepen dent deuterium sites. The room temperature cell parameters are a = 10. 3466(4) Angstrom and c = 5.0589(3) Angstrom, with a refined deuterium content of 2.4 D per formula unit. The 250 degrees C structure is esse ntially the same as the room temperature structure. The structure of t he deuterium solid solution of Ti3P at 300 degrees C has also been stu died using neutron powder diffraction. A new deuterium site was found but the structure was the same in other respects as that found at room temperature with only small changes in the cell parameters.