Unresolved crystal structure of the cubic Pm-3m MgIrHx impurity phase

Solve the crystal structure of the cubic Pm-3m MgIrH_x minority phase observed in autoclave-synthesized Mg–Ir hydride precursors, including the identification of atomic positions and hydrogen occupancy necessary to fully characterize the phase.

Background

Although the minority phase’s unit-cell volume was tracked under pressure to obtain its equation of state, the crystal structure itself was not solved. Determining the detailed structure, including hydrogen positions, is essential for unambiguous phase identification and for understanding its relationship to the main hydride phases.

Structural resolution would also clarify whether the phase corresponds to a hydride or an MgIr alloy and aid in interpreting its mechanical and electronic properties.