BOUND-STATES IN ELECTROLYTE-SOLUTIONS - THEORY OF ION ASSOCIATION

A new concept of ion association in electrolyte solutions is presented in this paper. The starting point for our theory is the activity expa nsion of osmotic pressure in the physical picture and the energetic de finition of bound states in the phase space of ions. The weight functi on describing the contributions of the bound states to the second clus ter coefficients is calculated. It is established that ion screening h as a substantial influence on the formation of bound states. The equat ion of state is written in the chemical picture by splitting the two-p article screened cluster coefficient into bound and free parts. We sho w that the bound part of the cluster coefficient in the physical pictu re can be identified with the association constant in the chemical pic ture. The mass action law is derived in a self-consistent way. (C) 199 6 American Institute of Physics.