Solid-liquid equilibria of (KCI + NH4CI + H2O) ternary system were investigated and it was found that there were five crystalline regions in the course of crystallization (respectively pure NH4CI, mNH(4)CI center dot KCI solid solution, NH4CI center dot nKCI solid solution, mixed mNH(4)CI center dot KCI and NH4CI center dot nKCI solid solution and pure KCI). The type of two solid solutions was determined by analysis of X-ray diffraction (XRD), Fourier transform infra-red (FTIR), lattice constant and density of solid solution crystals. It could conclude that they were limited substitutional solid solutions. Solid solubility (substitutional impurity in solvent) was measured at 25 degrees C and its variation was in accordance with Vergard's law. Moreover, thermal stability of two solid solutions was compared by TG-DTA. Results showed that both mNH(4)CI center dot KCI and NH4CI center dot nKCI shared the property of their mother phase and maintained its individual characteristics. (C) 2017 Elsevier B.V. All rights reserved.