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

## TL;DR

This study uses neutron diffraction to determine how deuterium atoms are arranged in molybdenum deuteride under high pressure.

## Contribution

The study confirms the crystal structure and deuterium occupancy in MoD1.15 under high pressure using neutron diffraction.

## Key findings

- Molybdenum deuteride has a P63/mmc space group and a composition of MoD1.15.
- Most deuterium atoms occupy octahedral sites, with some in tetrahedral sites.
- Deuterium atoms are at short distances of 1.49 and 1.90 Å from molybdenum atoms.

## Abstract

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 MoD1.15, showing that our data are sensitive to deuterium positions
and occupancies. In MoD1.15, 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.