Structure of Zr{sub 2}ON{sub 2} by neutron powder diffraction: The absence of nitride-oxide ordering
- Univ. of Exeter (United Kingdom). School of Chemistry
- Univ. of Oxford (United Kingdom). Inorganic Chemistry Lab.
The structure of the fluorite-related zirconium oxynitride Zr{sub 2}ON{sub 2} has been refined against a combination of laboratory X-ray and time of flight neutron powder diffraction data. The structure is of the bixbyite (C-M{sub 2}O{sub 3}) type. The high symmetry of the powder diffraction pattern does not allow one to easily distinguish between fully ordered, fully disordered, or partially ordered anion models. However, Rietveld refinements against both high and medium resolution neutron powder diffraction data clearly favor a statistical distribution of oxide and nitride anions over a single crystallographic site which is contrary to the predictions of previous calculations. The space group is Ia{bar 3} (No 206), with a = 10.13940(7) {angstrom} at 298 K and Z = 16. This symmetry and unit cell are retained at low temperatures (a = 10.1250(1) {angstrom} at 4.5 K). Partial oxidation reveals the existence of a phase with N{sub 2} molecules weakly bound and the stoichiometry ZrO{sub 2}(N{sub 2}){sub 0.028(1)}. The authors also report the isostructural hafnium oxynitride Hf{sub 2}ON{sub 2} (Ia{bar 3} with a = 10.0692(2) {angstrom} at 298 K as determined using laboratory X-ray diffraction data).
- OSTI ID:
- 696673
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 146; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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