The ion interaction approach developed by Fitter allows the prediction of various thermodynamic characteristics of multiple-solute electrolyte solutions, if the respective parameters for each type of single-solute electrolyte solution are known. The present paper discusses the Fitter approach to the calculations of the volumetric properties of single-solute electrolyte solutions. The databases for the densities and the apparent molal volumes versus concentrations were created at 298.15 degrees K using essentially all published relevant data for each single-solute electrolyte solution. Poor experimental data were discarded by a statistical treatment applied to these databases. Proper treatment of all good quality density and apparent molal volume data, in a wide range of concentrations from infinite dilution through saturation, allowed us to evaluate the volumetric ion interaction parameters (<(V)over bar (0)(MX)>, beta(MX)((0)V), beta(MX)((1)V), beta(MX)((2)V), and C-MX(V)) at 298.15 degrees K for 102 electrolytes. Strong linear relationships between the beta(MX)((1)V), beta(MX)((2)V), or C-MX(V), and beta(MX)((0)V) volumetric ion interaction parameters were observed for all analyzed solutes with slopes depending on the solute valency types. (C) 1996 American Institute of Physics and American Chemical Society.