(Cd,Zn)Te single crystals fabricated in our laboratory by Vertical Gradient Freeze Method were subjected to two types of experiments. In the first experiment, samples were annealed at temperatures 600-900°C under different Cd overpressures. They were quenched after annealing to room temperature and Hall effect and conductivity measurements were performed. In the second experiment, in situ Hall effect and conductivity measurements on neighbor samples were done also at temperatures 700-900°C. We determined equilibrium concentrations of defects at temperatures 700-900°C and the stoichiometry intrinsic line in the p-T diagram comparing the experiments and the theoretical model presented by Berding. Results of the presented analysis can be used to find optimal growth and annealing conditions to reduce precipitation of Cd/Te or to produce intrinsic material suitable for fabrication of (CdZn)Te gamma-ray detectors.