Hydration numbers and bulk properties of NH4+, Cl–, and NO3- ions in solution at 298.15 K: Concentration dependence

Abstract

A method is proposed for determining the hydration number of an individual ion within the approach (V. P. Korolev, J. Struct. Chem., 55, No. 3, 463 (2014)). In an infinitely dilute solution, the hydration numbers of ions are given by the formulas NH₄⁺, Cl^–(H₂O)₂, Cl⁻(H₂O)₄, and NO₃^-(H₂O)₇. The structure of aqueous complexes is discussed, and a structurally relevant parameter, i.e., the density of water of hydration, is determined. Salt concentration dependences are derived for the hydration number and apparent volume of NH₄⁺, Cl⁻, and NO₃^-ions. The density of the cationic (Н₂О-NH₄⁺) and anionic (Н₂О–Cl⁻ and Н₂О-NO₃^-) systems is calculated.