The entire phase diagrams of the ternary systems NaCl + NH4Cl + H2O, KCl + NH4Cl + H2O, NaCl + AICl(3) + H2O, and KCl + AICl(3) + H2O, as well as the solubilities of sodium and potassium chlorides in aqueous solutions of lithium chloride, were determined at T = (298 to 333) K. Additionally, the equilibrium concentrations of pure ammonium chloride, lithium chloride monohydrate salt, and aluminum chloride-6-hydrate were also measured over the same range of temperatures. The measured data were correlated as a function of temperature and content of the secondary electrolyte in the solvent by a least-squares method. The proposed empirical equations of fit allow fair agreement between calculated and experimental data, the invariant composition mixtures included, with standard deviations of fit to molality ranging from +/-(0.02 to 0.05) mol(.)kg(-1). In concentrated solutions of lithium and aluminum chlorides, the equilibrium concentrations of NaCl and KCl become very small. Therefore, because of the form of the optimization criterion chosen for the fit, the relative deviations between the two sets of data increase directly with the content of the secondary electrolyte.