High-pressure x-ray diffraction and ab initio study of Ni2Mo3N , Pd2Mo3N , Pt2Mo3N , Co3Mo3N , and Fe3Mo3N : Two families of ultra-incompressible bimetallic interstitial nitrides

We have studied by means of high-pressure x-ray diffraction the structural stability of Ni₂Mo₃N , Co₃Mo₃N , and Fe₃Mo₃N . We also report ab initio computing modeling of the high-pressure properties of these compounds, Pd₂Mo₃N and Pt₂Mo₃N . We have found that the nitrides remain stable in the ambient-pressure cubic structure at least up to 50 GPa and determined their equation of state. All of them have a bulk modulus larger than 300 GPa. Single-crystal elastic constants have been calculated in order to quantify the stiffness of the investigated nitrides. We found that they should have a Vickers hardness similar to that of cubic spinel nitrides such as γ-Si₃N₄ .