The solubility of ZnSO~4-Thr-H~2O system at 25℃ in the entire concentration range has been investigated by phase equilibrium method. The corresponding phase diagram and refractive index diagram have been constructed. The results indicate that system is a simple one, which does not have any new compounds. The compound of Zn(Thr)SO~4· H~2O, which is not reported in the literature, has been prepared in acetone-water mixture solvent. The compound is characterized by IR spectra, XRD, XPS and TG-DTG, as well as chemical and elemental analyses. The constant volume combustion energy of the complex, △~c~, ~c~o~o~rE, has been determined by a precision rotating bomb calorimeter at 298.15K. The standard enthalpy of combustion, △~c~, ~c~o~o~rH^θ, and standard enthalpy of formation, △~f~,~c~o~o~rH^θ, are calculated for the complex.

Key words: ZINC SULFATE, WATER, PHASE EQUILIBRIUM, THREONINE, ENTHALPY OF FORMATION