Formation of Molybdenum Deuteride at High Pressure: A Neutron Diffraction Study

The locations and occupancies of deuterium atoms in molybdenum deuteride were studied using time-of-flight neutron powder diffraction under pressures up to ∼6.2 GPa. We confirmed the P6₃/mmc space group and determined the overstoichiometric deuterium content to give a composition of MoD_1.15, showing that our data are sensitive to deuterium positions and occupancies. In MoD_1.15, the majority of the interstitial deuterium atoms occupy the octahedral sites, and the remainder occupy the tetrahedral sites and exhibit relatively short interatomic distances of 1.49 and 1.90 Å to molybdenum atoms.