A cluster theory for electrolytes

A simple extension of the Bjerrum theory is formulated and examined. Clusters of trimers as well as dimers are included. The intercluster partition function is evaluated in the mean spherical approximation. At low concentrations this cluster theory gives good results for the thermodynamic functions and for the radial distribution function for unlike pairs. The radial distribution function for like pairs is less satisfactory. The theory is less successful at higher concentrations but is always at least as good as the mean spherical approximation. © 1983 American Institute of Physics.