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Title: | Щодо природи поліморфізму тернарного селеніду LiAsSe(2) |
Other Titles: | On the nature of the polymorphism of the ternary selenide LiAsSe(2) |
Authors: | Сідей, Василь Іванович Семрад, О.О. Штейфан, А.Я. |
Issue Date: | 2014 |
Publisher: | Видавництво УжНУ "Говерла" |
Citation: | Сідей, В. І. Щодо природи поліморфізму тернарного селеніду LiAsSe(2) [Текст] / В. І. Сідей, О. О. Семрад, А. Я. Штейфан // Науковий вісник Ужгородського університету : Серія: Хімія / ред. кол.: С.Ю. Чундак (голова), І.Є. Барчій, С.М. Сухарев, В.Г. Лендєл та ін. – Ужгород : Видавництво УжНУ "Говерла", 2014. – Вип.2 (32). – C. 8–11. – Бібліогр.: с.11 (12 назв). |
Series/Report no.: | Хімія; |
Description: | In order to elucidate the reasons for the polymorphism observed for LiAsSe2, the crystal structures of a-LiAsSe2 and b-LiAsSe2 have been analyzed by using the ionic radii concept; additionally, the crystal structure of b-LiAsSe2 has been analyzed by using the bond valence model. Both the ionic radii concept and the bond valence model have indicated a rather high instability for the structure of b-LiAsSe2. Thus, the ionic radii of Li+ and As3+ are too small to form stable and undistorted coordination octahedra [LiSe6] and [AsSe6]; the bond valence sums calculated for the cations Li+ and As3+ of b-LiAsSe2 are deficient and surplus, respectively, while the two symmetrically independent Se2– anions of this structure are characterized by strongly uneven distribution of the bond valence sums. One may expect that heating of b-LiAsSe2 leads to a preferential increase of the thermal motion magnitude for the small cations; such cations have larger effective sizes, the difference between the ionic radii of the cations and anions becomes smaller and the distorted coordination octahedra [LiSe6] and [AsSe6] become the regular ones in the structure of a-LiAsSe2. |
Type: | Text |
Publication type: | Стаття |
URI: | https://dspace.uzhnu.edu.ua/jspui/handle/lib/944 |
Appears in Collections: | Науковий вісник УжНУ Серія: Хімія Випуск 2(32) - 2014 |
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File | Description | Size | Format | |
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ЩОДО ПРИРОДИ ПОЛІМОРФІЗМУ ТЕРНАРНОГО СЕЛЕНІДУ.pdf | 181.94 kB | Adobe PDF | View/Open |
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