Refinement of the Crystal Structure of Synthetic Chervetite, Pb2V2O7
| Autor: | Robert D. Shannon, Crispin Calvo |
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| Rok vydání: | 1973 |
| Předmět: | |
| Zdroj: | Canadian Journal of Chemistry. 51:70-76 |
| ISSN: | 1480-3291 0008-4042 |
| Popis: | The structure of synthetic chervetite has been refined by full matrix least-squares to a ωR = 0.029 using 1105 reflections. Unit cell dimensions are a = 13.3689(7), b = 7.1607(4), c = 7.1027(4) Å, β = 105935(5)°, and the space group is P21/a. The structure, originally solved by Kawahara, is a dichromate-type structure with a V2O74− group eclipsed to within 11 ± 5°. The Pb2+ ions are irregularly coordinated to 8 or 9 oxygens with distances from 2.40 to 3.20 Å. The distortion of the Pb–O distances is considerably greater than the corresponding distortions of the Sr–O distances in the similar β-Sr2V2O7 structure and is related to the tendency of Pb2+ to form directional covalent bonds. The V–O distances range from 1,665 to 1.720 Å for terminal oxygens and are 1.812 and 1.821 Å for the bridging oxygens. The V–O distances are consistent with the strengths of the Pb—O bonds. |
| Databáze: | OpenAIRE |
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