Polymorphism in the Sr-Bi System
| Autor: | Edward S. Grew |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Journal of Phase Equilibria and Diffusion. 42:818-823 |
| ISSN: | 1863-7345 1547-7037 |
| DOI: | 10.1007/s11669-021-00925-6 |
| Popis: | Eleven examples of hexagonal and orthorhombic polymorphs of intermetallic compounds having 5:3 stoichiometry are listed in the International Crystal Structure Database. A transition temperature between them has only been determined for the Yb–Sb and Sr–Bi systems, but results on the Sr–Bi system are discrepant with those on the Yb–Sb system, in which the phase relationships are well constrained by experimental data, for example, that the lower-temperature polymorph is the prototype orthorhombic Yb5Sb3 structure (αY5Sb3) and the higher temperature polymorph (βYb5Sb3) is isostructural with hexagonal Mn5Si3, with the transformation occurring at 1280 °C. In contrast, thermodynamic modeling on the Sr–Bi system give the inverse sequence of polymorphs with increasing temperature. It appears unlikely that the hexagonal Mn5Si3 structure type can be stable at higher temperatures than the orthorhombic Yb5Sb3 structure in one system, while orthorhombic Yb5Sb3 structure is the stable phase at higher temperatures in another system. The discrepancy can be attributed to the limited experimental data used to model the phase relationships in the Sr–Bi system. |
| Databáze: | OpenAIRE |
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