Convenient synthesis of nanocrystalline powders of phase-pure manganese nitride eta -Mn sub(3)N sub(2)

Manganese bis(trimethylsilyl)amide Mn[N(Si(CH sub(3)) sub(3)) sub(2)] sub(2) was used as a convenient material precursor to prepare pure manganese nitride nanopowders with reaction-controlled average crystallite sizes. The precursor was first reacted with liquid ammonia under reflux conditions and the resulting by-product was pyrolyzed under an ammonia flow at temperatures in the range 150-900 degree C. The powder products were characterized mainly by powder X-ray diffraction (XRD) diffraction, SEM/EDX examinations, and FT-IR and micro-Raman spectroscopies. In all cases, a pure phase of nanocrystalline eta -Mn sub(3)N sub(2) was detected by XRD as the exclusive manganese nitride product. The compound's nanopowders were extremely reactive toward air. Upon oxidation, they formed either MnO for a relatively better crystallized nitride from higher synthesis temperatures or Mn sub(3)O sub(4) after self-ignition of a poorly crystalline nitride from a lower synthesis temperature.