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 N-2(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 gamma-Mo2N (800 degrees C, N-2) and Mo2N (720 degrees C, N-2), Ta3N5 (650 degrees C, NH3), Fe3Mo3N (>650 degrees C, N-2), and a mixture of niobium nitride phases (800 degrees C, N-2). A previously unreported phase has been found in the Ba-Nb-N system.