The Defect Structure and Bonding of Zirconium Nitride Containing Excess Nitrogen
Zirconium nitride, containing 2.0 wt % Hf, is found to have a 25 = 4.57560 ± 0.00005 A (refraction correction included) and a linear thermal expansion coefficient α = 5.28 × 10 -6 deg -1 (10-60°). Its composition is (Zr, 2% Hf) 0.95 ± 0.03N, experimental density d 25° = 6.884 ± 0.003 g cm -3 (the X-ray density of the stoichiometric compound is 7.284 g cm -3). The unit cell contains 3.913 molecules with 3.5% of all sites (8/unit cell) vacant in the cationic and 1.1% in the anionic (N) sublattice. The excess of N atoms over the stoichiometric formula is 0.19 atom/unit cell. From purely chemical considerations the bonding appears to be more ionic than metallic and may be described as involving various electronic states of nitrogen (N 3-, N 0), imposing a high degree of ionic character on the nitride. However, no quantitative value could be assigned to the degree of ionic bonding.
M. E. Straumanis et al., "The Defect Structure and Bonding of Zirconium Nitride Containing Excess Nitrogen," Inorganic Chemistry, American Chemical Society (ACS), Jan 1966.
The definitive version is available at http://dx.doi.org/10.1021/ic50045a040
Materials Science and Engineering
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© 1966 American Chemical Society (ACS), All rights reserved.