On the interpretation of the static permittivities of aqueous ionic solutions

Abstract

It has been shown that one important factor in the lowering of the static permittivity of aqueous solutions of 1 : 1 electrolytes from its value in pure water is the volume occupied by the ions. Other factors involved include the number of irrotationally bound water molecules (n_irr) associated with the ions. The latter effect has been quantified on the basis of a simplified model of the solution. For solutions of quaternary ammonium salts negative values of n_irr are obtained, thus providing a quantitative basis for the concept of hydrophobic hydration.