Phase transition in the extreme: a cubic-to-triclinic symmetry change in dielectrically switchable cyanide perovskites
| Autor: | Monika Trzebiatowska, Adam Sieradzki, Anna Gągor, Paulina Peksa, Lucyna Macalik |
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| Rok vydání: | 2019 |
| Předmět: |
Diffraction
Phase transition Materials science 010405 organic chemistry Cyanide Transition temperature Dielectric Triclinic crystal system 010402 general chemistry 01 natural sciences Symmetry (physics) 0104 chemical sciences Inorganic Chemistry chemistry.chemical_compound Crystallography Formamidinium chemistry |
| Zdroj: | Dalton Transactions. 48:15830-15840 |
| ISSN: | 1477-9234 1477-9226 |
| Popis: | Two novel three-dimensional metal-organic compounds of formula FA2KM(CN)6, where M = Co, Fe and FA = formamidinium (CH(NH2)2+), have been found to crystallize in a perovskite-like architecture. They have been investigated by X-ray diffraction, dielectric and spectroscopic methods as a function of temperature in order to determine the interactions in the crystals and the mechanism of phase transitions occurring at ca. 321 K upon heating. The phase transitions in both crystals are of first order and originate from the ordering of the formamidinium cations below TC. Symmetry reduction (cubic-to-triclinic) seems to be the strongest upon temperature decrease among known metal-organic frameworks. These materials have been proposed as possible switchable dielectrics with a convenient near-room-temperature transition temperature. |
| Databáze: | OpenAIRE |
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