Where the extraordinaries meet: a cascade of isosymmetrical superionic phase transitions and negative thermal expansion in a novel silver salt-inclusion borate halideстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 22 июня 2022 г.
Аннотация:A new silver iodide borate Ag3B6O10I, is a promising material as a solid-state electrolyte, with a δ ↔ γ ↔ β ↔ α cascade of the isosymmetric superionic phase transitions. Its crystal structure is composed of two sublattices, the “host” B-O covalent part from B6O13 6B:3Δ3□:[φ]|<Δ2□>|<Δ2□>|<Δ2□>| corner-sharing hexaborate groups, and the “guest” Ag-I ionic part. The transitions are associated with the structural re-arrangements of the latter with a stepwise “melting” of silver sublattice, and give rise to increase of conductivity to 0.005 S·cm−1 at 99 °C. Exceptionally large room-temperature anharmonicity of silver vibration was described. The silver ions migration leads to the negative thermal expansion (NTE) at 25–400 °C. The sodium analogue, Na3B6O10I, with “normal” perovskite-like structure was obtained. The structural diversity in the M3B6O10X family can be rationalized considering the difference in the ionic radii of X– anions and M+ cations.