β-Ca11B2Si4O22: six-fold twinning, crystal structure and thermal expansion
| Autor: | S. N. Volkov, Rimma S. Bubnova, Vladimir V. Shilovskikh, Valentina Yukhno |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
02 engineering and technology Fold (geology) Crystal structure 021001 nanoscience & nanotechnology 010403 inorganic & nuclear chemistry Condensed Matter Physics 01 natural sciences Thermal expansion 0104 chemical sciences Inorganic Chemistry Crystallography General Materials Science 0210 nano-technology X ray analysis Crystal twinning |
| Zdroj: | Zeitschrift für Kristallographie - Crystalline Materials. 233:379-390 |
| ISSN: | 2196-7105 2194-4946 |
| Popis: | The low-temperature polymorphβ-Ca11B2Si4O22crystallizes as a monoclinic structure [space group isP21/c,a=14.059(9),b=6.834(5),c=10.597(7) Å,β=100.735(8)°]. The crystal investigated by single-crystal X-ray diffraction was a twin composed of six individuals. The crystal structure is similar to that of mineral spurrite, Ca5(SiO4)2CO3, and can be described as a framework of [CaO5] and [CaO6] polyhedra, the cavities of which are filled with [SiO4] and [BO3] groups. The orientation relationship of twin domains was investigated by electron backscatter diffraction (EBSD). Thermal expansion was studied by high-temperature X-ray powder diffraction. It is slightly anisotropic:α11=10,α22=16,α33=12×10−6°C−1at 200°C. |
| Databáze: | OpenAIRE |
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