Calcium hypophosphite has been widely used as an anti-corrosive agent, flame retardant, fertilizer, assistant for Ni electroless plating, and animal nutritional supplement. High purity calcium hypophosphite can be synthesized via the replacement reaction of sodium hypophosphite and calcium chloride. In this work, the (solid + liquid) phase equilibria of (Ca(H2PO2)(2) + CaCl2 + H2O) and (Ca(H2PO2)(2) + NaH2PO2 + H2O) ternary systems at T= 323.15 K were studied experimentally via the classical isothermal solubility equilibrium method, and the phase diagrams for these two systems were obtained. It was found that two solid salts of CaCl2 center dot 2H(2)O and Ca(H2PO2)(2) exist in the (Ca(H2PO2)(2) + CaCl2 + H2O) system, and three salts of Ca(H2PO2)(2), NaH2PO2 center dot H2O and one incompatible double salt, NaCa(H2PO2)(3) occur in the (ca(H2PO2)(2)+ NaH2PO2+ H2O) system. (C) 2015 Elsevier Ltd. All rights reserved.