Synthesis of Transition-Metal Nitrides from Nanoscale Metal Particles Prepared by Homogeneous Reduction of Metal Halides with an Alkalide

Transition-metal nitrides have been synthesized by heating nanoscale metal particles under flowing N2(g) or NH3(g). In some cases reaction temperatures are significantly lower than those required by conventional heating procedures. Nanoscale metal particles of Mo, Nb, Ta, Fe−Mo, Fe−Nb, and Cu−Nb were prepared by reduction of the respective metal chloride or mixture of chlorides with the sodide, [K+(15-crown-5)2]Na-, in dimethyl ether solution. The previously characterized nitrides that were prepared (with synthesis conditions indicated) include γ-Mo2N (800 °C, N2) and Mo2N (720 °C, N2), Ta3N5 (650 °C, NH3), Fe3Mo3N (>650 °C, N2), and a mixture of niobium nitride phases (800 °C, N2). A previously unreported phase has been found in the Ba−Nb−N system.