High-Pressure Synthesis, Electron Energy-Loss Spectroscopy Investigations, and Single Crystal Structure Determination of a Spinel-Type Gallium Oxonitride Ga2.790.21(O3.05
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- 作者：Hubert Huppertz ; Stefanie A. Hering ; Carmen E. Zvoriste ; Stefan Lauterbach ; Oliver Oeckler ; Ralf Riedel ; Isabel Kinski
- 刊名：Chemistry of Materials
- 出版年：2009
- 出版时间：May 26, 2009
- 年：2009
- 卷：21
- 期：10
- 页码：2101-2107
- 全文大小：181K
- 年卷期：v.21,no.10(May 26, 2009)
- ISSN：1520-5002
文摘
Under high-pressure/high-temperature conditions of 5 GPa and 1250 °C, the cubic phase Ga2.790.21(O3.05N0.760.19) ( = vacancy) was synthesized in a Walker-type multianvil apparatus. For the first time, the crystal structure of a gallium oxonitride was determined on the basis of single crystal X-ray diffraction data. The cubic spinel-type gallium oxonitride crystallizes in the space group Fdm (No. 227) with a lattice parameter a0 = 827.8(2) pm. The combination of energy-dispersive X-ray spectroscopy (EDS) with electron energy-loss spectroscopy (EELS) allowed the quantification of nitrogen and oxygen for structural refinement. In the literature dealing with oxonitrides, crystal defects in spinel-type materials are handled with different models, mainly the approximation of a constant anion model. The present results indicate that this model is questionable, and one should also take into account a model with both cation and anion vacancies. Furthermore, a linear relationship between the lattice parameters and the ratio N/O in the gallium oxonitrides is questionable.