アルカリケイ酸塩融体中のスズイオンの酸化還元平衡

概要

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Sn^<4+>-Sn^<2+>redox in binary alkali silicate melts was studied by means of differential pulse voltammetry. The half-wave potential, E_<1/2> of the reduction of Sn^<4+> to Sn^<2+> shifts toward the negative with changing the alkali metal ions from Li^+ through Na^+, K^+ and Cs^+, at a fixed concentration for each alkali metal oxide. Conversely, E_<1/2> shifts to the positive with an increase in the content of each of the alkali oxide. This tendency for Sn^<4+>-S2^<2+> redox was different from those of Sb^<5+>-Sb^<3>+ and Cr^<6+>-Cr^<3+> redox. The presence of Sb^<5+> and Cr^<6+> result in a strong acid, which leads to E_<1/2> shift to the negative with an increase in basicity. These results for Sn ions can be interpreted in terms of complex formations of Sn^<4+> and Sn^<2+> in which the coordination numbers of the oxide ion for both ions do not differ significantly and their equilibrium constants for complex formation depend largely on the alkali species.
社団法人日本セラミックス協会の論文
1999-04-01