Mean spherical model for asymmetric electrolytes

The mean spherical approximation for the primitive model of electrolytic solutions is solved for the most general case of an arbitrary charge and size. It is found that the excess thermodynamic properties are scaled to the charge and the size by means of a rational expression involving a single parameter. This parameter is found by solving an algebraic equation. The explicit form of this equation is obtained for the cases of a binary mixture and in the limit of low concentrations.