On the structure of hydration shells of alkali metal ions in aqueous solutions

On the basis of the experimental equilibrium distributions of ions with respect to hydration degree in aqueous solutions, it has been suggested that the hydration shells of alkaline metal ions have the interior and the exterior parts. The former shows the structure defined by direct interaction of water molecules with the ions and the latter demonstrates the structure transient between that specific for interior regions and pure water. The capacities of the interior regions have been shown to depend on the electrolyte concentration unlike the exterior ones. In addition, the probability to find a water molecule in a potential well of the exterior region is substantially lower than in the interior region or in pure water.