Transformation of scheelite M2MoTiO8 (M = Eu, Gd, Dy, Y) and zircon MVO4 (M = Ce, Sm, Gd, Dy) oxides to fluorite oxynitrides and perovskite oxides under mild ammonolysis conditions
| Autor: | Neha Bhardwaj, Sitharaman Uma, Vidhu Malik |
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| Rok vydání: | 2019 |
| Předmět: |
Thermogravimetric analysis
Materials science 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Fluorite Magnetic susceptibility 0104 chemical sciences Crystallography chemistry.chemical_compound X-ray photoelectron spectroscopy chemistry Oxidation state Scheelite General Materials Science 0210 nano-technology Powder diffraction Perovskite (structure) |
| Zdroj: | Solid State Sciences. 89:114-120 |
| ISSN: | 1293-2558 |
| DOI: | 10.1016/j.solidstatesciences.2018.12.013 |
| Popis: | Anion-deficient fluorite oxynitrides, M2MoTiO5-xN2+x-δ (M = Eu, Gd, Dy, Y; x = 0.0–0.2; δ (anion vacancies) = 0.2–0.4) have been synthesized by the reaction of single phase scheelite, M2MoTiO8 precursors with nitrogen enriched ammonia gas at 800–850 °C. The oxynitrides were characterized by elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), magnetic susceptibility and X-ray photoelectron spectroscopy (XPS) measurements. The results suggested that the products crystallizing in fluorite structure with an average oxidation state of Mo varying between 5.5 and 5.8 without any change in Ti4+ state. Similar attempts to react MVO4 (M = Ce, Sm, Gd, Dy), zircon oxides resulted only in V3+ containing perovskite (MVO3) oxides. The extent of nitrogen incorporation to form oxynitrides varies depending upon the stabilization of oxides in lower oxidation states. |
| Databáze: | OpenAIRE |
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