School of Molecular Sciences, Center for Materials of the Universe, Arizona State University, P.O. Box 871604, Tempe, AZ 85287-1604, USA.
School for Engineering of Matter, Transport and Energy, Center for Materials of the Universe, Arizona State University, P.O. Box 871604, Tempe, AZ 85287-1604, USA.
Molecules. 2023 Jun 7;28(12):4623. doi: 10.3390/molecules28124623.
The paper analyzes the relationships among acid-base interactions in various oxide systems and their thermodynamics. Extensive data on enthalpies of solution of binary oxides in oxide melts of several compositions, obtained by high-temperature oxide melt solution calorimetry at 700 and 800 °C, are systematized and analyzed. Oxides with low electronegativity, namely the alkali and alkaline earth oxides, which are strong oxide ion donors, show enthalpies of solution that have negative values greater than -100 kJ per mole of oxide ion. Their enthalpies of solution become more negative with decreasing electronegativity in the order Li, Na, K and Mg, Ca, Sr, Ba in both of the commonly used molten oxide calorimetric solvents: sodium molybdate and lead borate. Oxides with high electronegativity, including PO, SiO, GeO, and other acidic oxides, dissolve more exothermically in the less acidic solvent (lead borate). The remaining oxides, with intermediate electronegativity (amphoteric oxides) have enthalpies of solution of between +50 and -100 kJ/mol, with many close to zero. More limited data for the enthalpies of solution of oxides in multicomponent aluminosilicate melts at higher temperature are also discussed. Overall, the ionic model combined with the Lux-Flood description of acid-base reactions provide a consistent and useful interpretation of the data and their application for understanding the thermodynamic stability of ternary oxide systems in solid and liquid states.
本文分析了各种氧化物系统中酸碱相互作用及其热力学之间的关系。通过在 700 和 800°C 下的高温氧化物熔体溶液 calorimetry 获得了广泛的二元氧化物在几种组成的氧化物熔体中的溶解焓数据，并对其进行了系统分析和研究。具有低电负性的氧化物，即碱金属和碱土金属氧化物，它们是强的氧离子供体，其溶解焓具有大于-100 kJ/mol 的负数值。在两种常用的熔融氧化物量热溶剂：钼酸钠和硼酸铅中，随着电负性的降低，其溶解焓变得更负，顺序为 Li、Na、K 和 Mg、Ca、Sr、Ba。具有高电负性的氧化物，包括 PO、SiO、GeO 和其他酸性氧化物，在酸性较小的溶剂（硼酸铅）中更易溶解。剩余的具有中间电负性的氧化物（两性氧化物）的溶解焓在+50 和-100 kJ/mol 之间，许多接近零。还讨论了在更高温度下在多组分铝硅酸盐熔体中氧化物的溶解焓的更有限的数据。总体而言，离子模型结合 Lux-Flood 对酸碱反应的描述为数据及其在理解固液状态下三元氧化物系统热力学稳定性中的应用提供了一致且有用的解释。
