Structural stability, phase transition, and mechanical and electronic properties of transition metal nitrides MN (MÂ =Â Tc, Re, Os, and Ir): First-principles calculations

► Structural stability, phase transition, and electronic properties of MN were studied. ► NbO-type ReN and TcN and Pmn21-type IrN and OsN are preferred energetically. ► Phase transition between NbO-type and NiAs-type structure occurs for ReN and TcN. ► NiAs-type ReN and Pmn21-type OsN have high Vickers hardness. ► The Pmn21-type IrN is a semiconductor material.