In this paper the cluster approaches to calculate thermodynamic parameters of zinc chalcogenides was proposed. Specifically determined enthalpy of formation of crystal data and the phase transition temperature for polymorphic sphalerite-wurtzite modifications. The calculation was carried out within the cluster approximation using the restricted Hartree-Fock method, using the valence basic set SBKJC [1], which includes an effective core potential, using FireFly. For the calculation used four molecular models of zinc chalcogenides. The first cluster includes the zinc atom is surrounded by two ligands and has the general formula ZnC2H2X4 (X = S, Se, Te). The second cluster, which Zn4C6H6X13 general formula contains sulfur atom surrounded by four atoms of zinc, which corresponds to the real placement of atoms in the crystal, all these atoms is fourcoordinated. For the saturation limit relations used six ligands of HCX2. Wurtzite structure was investigated using two models. The first (general formula Zn15H15) is the base for calculating the spatial and electronic structure and thermochemical quantities, it consists of 30 atoms and contains of two four-coordinated pairs, six three-coordinated pairs and seven two-coordinated pairs of atoms. As a result of calculation obtained values of enthalpy of formation models, combining them in view of the coordination models allowed to remove the boundary conditions and thus to estimate the corresponding values for the real crystals of sphalerite and wurtzite. It was also obtained thermodynamic characteristics at different temperatures based on the calculated vibrational spectra of the nanoparticles. These data are built graph of Gibbs energy on temperature for two polymorphic modifications, where the intersection point corresponds to the phase transition temperature. The calculated value of this quantity is 11910С, slightly above the experimental data (1175оC [2]) for volume. As a result of quantum-chemical calculations verified the suitability of molecular models to compare the properties of wurtzite and sphalerite and determine the phase transition temperature. This approach proved to be quite suitable for calculating the heats of formation and phase transition temperature. Well played the main differences of polymorphs: – bond length is shorter in wurtzite; – sphalerite is thermodynamically more stable. Satisfactory accuracy of the calculation is due to the choice of the appropriate model, and the mutual elimination of systematic errors.figure[1] M.Krauss, W.J.Stevens Ann.Rev.Phys.Chem. 35 (1985), 357-385. [2] E. Spano, S. Hamad, C.R. Catlow. J. Phys. Chem. 107 (2003), 10337-10340.