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Thermodynamic characterization of the amphotericity of oxides and hydroxides of group 111A elements in aqueous mediaстатья
Информация о цитировании статьи получена из
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 15 февраля 2024 г.
- Автор: Shkol'nikov E.V.
- Журнал: Russian Journal of Applied Chemistry
- Том: 81
- Номер: 12
- Год издания: 2008
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 2088
- Последняя страница: 2094
- DOI: 10.1134/S1070427208120082
- Аннотация: The dependences of molar solubility of solid oxides M203 on pH value of aqueous medium at 25°C, as well as acid-base equilibrium constants in aqueous media for stable crystalline oxides M2O3 crystalline and dissolved hydroxides M(OH)3 where M - B, Al, Ga, In, Tl.1 have been calculated by the thermodynamic method taking into account the formation of hydroxocomplexes. The molar solubility in water of solid oxides MO1.5 (M is an element of group 111A) is determined mainly by neutral complexes M(OH)3, is very low (10-8-10-5 mol - l-1 at 250C, except for BO1.5) and depends on composition and structure, significantly decreasing in the transition from amorphous to stable crystalline modification.2 The influence of pH value on the solubility of solid oxides M2O3 in aqueous alkaline and acidic media at 25oC has been calculated by the thermodynamic method and the amphoteric parameter A >1 increasing in the B→ Tl→ In → Al → Ga series has been determined. The pH values of acidic medium below which M3+ cations are not bound in hydroxocomplexes have been determined.3. Taking into account the formation of hydroxocomplexes, the minimum solubility and pH values of the most complete precipitation of amphoteric oxides of aluminum, gallium, indium and thallium (111) have been calculated.4. Calculation of thermodynamic constants of heterogeneous acid-base equilibria in aqueous media, as well as step constants of basicity and acidity of neutral complexes M(OH)3 indicates the acidic nature of boron oxide and hydroxide, the predominance of weak acidic properties over weak basic properties in oxide and hydroxide.
- Добавил в систему: Школьников Евгений Васильевич