Synthesis of Transition Metal Nitride by Nitridation of Metastable Oxide Precursor.

Metastable amorphous MoO2, obtained by reduction of aqueous (NH4)6Mo7O24 solutions with hydrazine (70 °C, 0.5 h followed by heating under a flow of Ar at 300 °C for 2 h) transforms into face-centered cubic γ-Mo2N in flowing NH3 at 400 °C and then into hexagonal δ-MoN by increasing the temperature to 600 °C.