[en] P_total-T-x state diagram of Si-Te system was plotted on the basis of tensimetric data and results of DTA, X-ray phase analysis. Si₂Te₃ compound, melting at 1159 K according to peritectic reaction and sublimating incongruently, exists in the system. Si₂Te₃ under polymorphous transformation at 681-683 K. Boundaries at Si₂Te₃ homogeneity region were determined by tensimetric method with accuracy of 0.04-0.06 at %. Si₂Te₃ crystals belong to trigonal syngony, lattice parameters a=0.7427±0.0007, c=1.3475±0.0010 nm, sp.gr. P3-bar1c, density-4.56±0.01 g/cm³