Chalcogenides by Reduction of their Dioxides in Ultra‐Alkaline Media
| Autor: | Ralf Albrecht, Michael Ruck |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
crystal structure
spectroscopy Aqueous solution hydroflux Potassium Inorganic chemistry Arsenate Chalcogenides | Very Important Paper chemistry.chemical_element Electron donor General Chemistry Redox Catalysis Chalcogen symbols.namesake chemistry.chemical_compound chemistry tellurium symbols Isostructural Raman spectroscopy selenium Research Articles Research Article |
| Zdroj: | Angewandte Chemie (International Ed. in English) |
| ISSN: | 1521-3773 1433-7851 |
| Popis: | The reaction of chalcogen dioxides ChO2 (Ch=Se, Te) with As2O3 in a 30 molar KOH hydroflux at about 200 °C yielded crystals of potassium trichalcogenides K2 Ch 3 with dimensions up to 2 cm. Arsenic trioxide acts as electron donor and is oxidized to arsenate(V). The new heterochalcogenide anion (TeSe2)2− formed when starting from SeO2 and TeO2 simultaneously. The compound K2TeSe2 crystallizes isostructural to K2S3 and K2Se3. The unexpected redox reaction as well as the precipitation of hygroscopic compounds from an aqueous solution are attributed to a strongly reduced activity of water. The reactions were studied by Raman and UV/Vis spectroscopy. Depending on the concentration of As2O3, colorless monochalcogenide Ch 2− or orange Se2 2− and purple Te2 2− anions are dominating the solutions. The unexpected reduction of selenium(IV) and tellurium(IV) oxides to chalcogenides was achieved under ultra‐alkaline conditions by using As2O3 as reducing agent. By optimization of the reaction conditions, large crystals of K2Se3, K2Te3 and K2Se2Te were grown within two days. In the latter compound, the novel mixed chalcogenide anion (SeTe)2− was discovered. |
| Databáze: | OpenAIRE |
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