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Zn{sub 3}N{sub 2} powders were prepared by ammonolysis reactions at 600 deg. C and examined by thermogravimetric analysis, powder X-ray and neutron diffraction. The powders obtained in this way are unstable in an oxygen atmosphere above 450 deg. C. In an argon atmosphere, the powders are stable up to their decomposition point at around 700 deg. C. Structural models obtained from Rietveld refinements against the powder neutron diffraction data indicate that the Zn{sub 3}N{sub 2} powders so-prepared have the anti-bixbyite structure and are almost certainly stoichiometric with no compelling evidence of nitrogen vacancies. Further, no evidence was found for aliovalent oxygen substitution at the nitrogen sites. The calculated bond valence sums imply that Zn{sub 3}N{sub 2} cannot be described as a 100% ionic compound. The structural findings are supported by photoluminescence measurements that reveal a band gap of approximately 0.9 eV. - Graphical abstract: Zn{sub 3}N{sub 2} powders prepared by careful ammonolysis reactions form with the anti-bixbyite structure and are almost certainly stoichiometric with no evidence for aliovalent oxygen substitution at the nitrogen sites. Zn{sub 3}N{sub 2} cannot be described as a 100% ionic compound and PL measurements reveal a narrow band gap of approximately 0.9 eV.

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 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.