Abstract
Pure, crystalline, fine particulate calcium zincate was prepared. Its chemical composition, 
was established by chemical analysis, weight loss in thermogravimetric analysis, and by x‐ray powder diffraction pattern. Its solubility in different 
solutions at 298 K was determined. The solubility data were used to determine the activities of 
and 
with respect to pure solid 
and liquid water, respectively, in calcium zincate. They were also used to determine the vapor pressure of water over calcium zincate and other thermodynamics properties of this system. The equilibrium constant of the reaction 
was found to be 
. The standard free energy of formation of calcium zincate was found to be 
at 298 K. The standard heat of formation was found to be −665 cal/mol, and the standard entropy of formation was found to be 3.35 cal/deg/mol.