The sites and dynamics of D in VD0.50, VD0.40 and VD0.57 were studied by means of X-ray diffraction, differential scanning calorimetry and 2H nuclear magnetic resonance. The VD0.40 consisted of the body-centered cubic, αD, and body-centered tetragonal, βD, phases at room temperature. Only the octahedral sites were occupied in the βD phase. In VD0.50, which consisted of the body-centered tetragonal βD phase at room temperature, the octahedral site was predominantly occupied, with a small occupancy of the tetrahedral sites in the βD phase. The VD0.57 was composed of body-centered cubic αD’ (a high D-concentration version of the αD phase) and body-centered tetragonal βD phases at room temperature. The occupancy of the tetrahedral sites was observed. The mean activation energy, ED, for D diffusion was much larger for the octahedral sites than for the tetrahedral sites, and the diffusion was also much slower in the octahedral sites. The mean ED values for the octahedral sites were almost the same in the βD phase of VD0.40 and VD0.50. However, the distribution of the mean residence time was much wider in VD0.50 than in VD0.40.

Deuterium Diffusion in Vanadium Deuterides (VDx; 0.4 ≤ x ≤ 0.6) Studied by 2H NMR. S.Hayashi: Journal of Solid State Chemistry, 2004, 177[3], 824-33