Structural Properties of Nonstoichiometric Barium and Strontium Peroxides: BaO2−x (1.97≥2−x≥1.72) and SrO2−x (1.98≥2−x≥1.90)
| Autor: | Markus Königstein |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Strontium
Inorganic chemistry Oxide chemistry.chemical_element Barium Crystal structure Condensed Matter Physics Peroxide Electronic Optical and Magnetic Materials Inorganic Chemistry chemistry.chemical_compound Tetragonal crystal system chemistry Strontium peroxide Materials Chemistry Ceramics and Composites Physical and Theoretical Chemistry Stoichiometry |
| Zdroj: | Journal of Solid State Chemistry. 147:478-484 |
| ISSN: | 0022-4596 |
| DOI: | 10.1006/jssc.1999.8402 |
| Popis: | The crystal structures of eight single crystals of barium and strontium peroxide, prepared by high pressure–high temperature synthesis, were determined by X-ray diffraction. The crystallographic data were successfully refined in the calcium carbide structure (space group I4/mmm, Z=2). The results clearly indicate that the peroxides are nonstoichiometric compounds, MO2−x (M=Ba, Sr), with a peroxide deficiency and that oxide ions are present on interstitial lattice sites. The composition rage extends from near stoichiometry to compounds with a total oxygen content of 1.72 in the barium and 1.90 in the strontium peroxide. We find that the oxide ions, replacing the peroxide molecular ions, occupy an interstitial position that is in the middle of the replaced peroxide molecular ion. A decrease of the peroxide content in the crystals results in a decreased c-axis of the tetragonal unit cell of the structure, while the a-axis is almost constant. Furthermore, the peroxide bond length decreases, as was confirmed by Raman spectroscopy. |
| Databáze: | OpenAIRE |
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