Electrochemical Study on Redox Behavior of the multivalent Metal Ions in the glass Melts

Sn^<4+>-Sn ^<2+> and Fe^<3+>-Fe ^<2+> equilibrium in alkali borate and silicate melts was studied by means of differential pulse voltam\.含有六层玻璃的半波潜力，当它们排出20摩尔%时，由于温度下降和氧化铝的增加而产生负面影响。当钾氧化物少于20摩尔%时，数据可以在两个减少峰值下拟合，即Fe^<3+>-含有复杂的Fe^<3 +>到Fe^<2+>。Sn^<4+>-Sn ^<2+>在Borate Melts中的equilibrium转移到Na_2O含量中的负增量和温度中的降解。在另一手上，半波潜力在硅熔融中转移到积极增加Na_2O含量。可以在Sn^&lt;4+&gt;和Sn^&lt;2+&gt;的复杂形式的术语中解释结果，其中氧化物的协调数的两个离子都没有显著差异，而equilibrium constants的复杂形成取决于alkali species。The ^<29>Si and ^<31>P nuclear magnetic resonance （NMR）化学位移和Q_n distribution in ternary sodium phosphosilicate glasses were examined。当P_2O_5含量增加到SiO_2等于0.1和0.05时，6-协调硅原子出现。6-coordinated硅原子的存在可能会出现在玻璃[P_2O_5]/[Na_2O]组合比单位大。From the NMR spectra of 30 Na_2 O·5 SiO_2· 65[（1-x）P_2 O_5·xB_2 O_3] glasses， the distribution curves derived from the decon\of the spectra by component signal of each phosphate and borate species agree with those calculated using species with different [Na_2 O] / [P_2 O_5] ratios when P_2 O_5 reacts with Na_2 O and B_2 O_3 preferably。

The Sn^<4+>-Sn^<2+> and Fe^<3+>-Fe^<2+> equilibrium in alkali borate and silicate melts was studied by means of differential pulse voltammetry. The half-wave potentials in Fe-containing glasses become negative with decrease of temperature and increase of alkali oxide when they exceed 20 mol%. When alkali oxide is less than about 20 mol%, the data can be fitted by two reduction peaks, i.e. the Fe^<3+>-containing complex and free Fe^<3+> to Fe^<2+>. The half-wave potentials of Sn^<4+>-Sn^<2+> equilibrium in borate melts shift to the negative with an increase in Na_2O content and a decrease in temperature. On the other hand, the half-wave potentials in the silicate melts shift to the positive with an increase in Na_2O content. There results 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.The ^<29>Si and ^<31>P nuclear magnetic resonance (NMR) chemical shifts and the Q_n distribution in ternary sodium phosphosilicate glasses were examined. When the P_2O_5 content increases at fixed mole fractions of SiO_2 equal to 0.1 and 0.05, the 6-coordinated silicon atoms appear. The presence of 6-coordinated silicon atoms is expected in glasses where the [P_2O_5]/[Na_2O] composition ratio is greater than unity. From the NMR spectra of 30Na_2O ・ 5SiO_2 ・ 65[(1-x)P_2O_5 ・ xB_2O_3] glasses, the distribution curves derived from the deconvolution of the spectra by component signal of each phosphate and borate species agree with those calculated using species with different [Na_2O] / [P_2O_5] ratios when P_2O_5 reacts with Na_2O and B_2O_3 preferably.