Structural chemistry of Cu₃N powders obtained by ammonolysis reactions

Powder samples of Cu₃N prepared from a CuF₂ precursor using ammonolysis reactions have been examined by powder X-ray and neutron diffraction, and scanning electron microscopy (SEM). Rietveld refinements against the powder diffraction data confirm that this compound is cubic, space group P m over(3, -) m, with nitrogen atoms located at the corners of the unit cell and the copper atoms occupying the centres of the unit cell edges. The neutron diffraction data confirmed that both nitrogen and copper sites are fully occupied and showed no evidence for nitrogen non-stoichiometry or the presence of interstitial copper atoms at the centre of the unit cell. The SEM study reveals that the Cu₃N powders are composed of plate-shaped particles of sub-micron size. The overall results indicate that the synthetic procedure reported here can be used to prepare reproducibly large amounts of stoichiometric Cu₃N powders of high purity.