The isopiestic method was used to determinate isopiestic molality and osmotic coefficients in single salt solutions of LiCl H 2O(molality range from 0.5 to 9.0 mol·kg -1 ),CaCl 2 H 2O(molality range from 0.35 to 5.2 mol·kg -1 ) and multisalt solution LiCl CaCl 2 H 2O(ionic strength range from 0.5 to 15.7 mol·kg -1 ) at 298.15K,from which Pitzer’s interaction parameters of single salt ,mixed salts of the systems were obtained.The mean ionic activity coefficients of LiCl、CaCl 2 in pure and mixed solutions were reported.
