Entropy of electrolytes

The entropy of 1–1 and 2–2 model electrolytes is calculated from an expansion in terms of the multiparticle correlation functions. For electrolytes, a simple truncation of this expansion is never sufficient for the accurate calculation of the entropy, even in the limit of low concentration, in marked contrast to the behavior for short‐ranged potentials. However, a partial, but infinite‐order, summation of the expansion is shown to yield both the correct low‐concentration limit and excellent results over a wide range of concentrations for both 1–1 and 2–2 electrolytes. The consequences of this result for some earlier applications of the entropy expansion to electrolytes are discussed.