Controlling multiple orderings in metal thiocyanate molecular perovskites Ax{Ni[Bi(SCN)6]}
| Autor: | Sanliang Ling, Jie Yie Lee, Matthew J. Cliffe, Laura Cañadillas-Delgado, Mark S. Senn, Stephen P. Argent |
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| Rok vydání: | 2021 |
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| Zdroj: | 'Chemical Science ', vol: 12, pages: 3516-3525 (2021) |
| ISSN: | 2041-6539 2041-6520 |
| Popis: | We report four new A-site vacancy ordered thiocyanate double double perovskites, Image ID:d0sc06619b-t1.gif, A = K+, NH4+, CH3(NH3)+ (MeNH3+) and C(NH2)3+ (Gua+), including the first examples of thiocyanate perovskites containing organic A-site cations. We show, using a combination of X-ray and neutron diffraction, that the structure of these frameworks depends on the A-site cation, and that these frameworks possess complex vacancy-ordering patterns and cooperative octahedral tilts distinctly different from atomic perovskites. Density functional theory calculations uncover the energetic origin of these complex orders and allow us to propose a simple rule to predict favoured A-site cation orderings for a given tilt sequence. We use these insights, in combination with symmetry mode analyses, to show that these complex orders suggest a new route to non-centrosymmetric perovskites, and mean this family of materials could contain excellent candidates for piezo- and ferroelectric applications. |
| Databáze: | OpenAIRE |
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