Condition diagram of the Sb₂Te₃–La₂Te₃ cut has been researched  by the differential, thermal, X-ray, microstructural analysis methods as well as microhardness and density measurement. It was found that cut is the quasibinary section of La– Sb–Te triple system. In the system there forms triple chemical combination consists on LaBiTe₃ crystallized in hexagonal lattice with the following parameters: a=4.24 c=30.64 Å  (c/a=7.21). Solubility on Sb₂Te₃ side at  room temperature is 6 mol.%. Electrophysical properties of LaSbTe₃  compound  have  been investigated too.