Significant structure theory applied to electrolyte solution.

The significant structure theory has been successfully applied to an aqueous NaCl solution. Liquid water is assumed to have a domain structure and the ions are hydrated by water molecules. The partition function is composed of the partition function for the water and that for the salt, and the excess free energy term from the Debye-Hückel theory is also added. The thermodynamic properties, such as molar volume, vapor pressure, entropy of vaporization, and heat capacity, as well as the dielectric constant are calculated over the whole concentration ranges and wide temperature ranges. The agreement between theory and experiment is satisfactory.