The analytical multi 3D model of phase diagram of the Tl₉TbTe₆–Tl₈Pb₂Te₆–Tl₉BiTe₆ system was obtained as temperature dependence on the composition using the Multipurpose Genetic Algorithm (MGA). It was determined that the system is characterized by the formation of continuous solid solutions with tetragonal Tl₅Te₃-type structure (δ-phase). The boundaries of the uncertainty band for the liquidus and solidus surfaces of the δ-phase and the TlTbTe₂ compound are determined. The thermodynamic functions of mixing of the solid solutions depending on the composition and temperature are determined based on the model of regular solutions of non-molecular compounds. It was established that the δ-phase possess thermodynamic stability in the entire concentration interval

doi.org/10.32737/0005-2531-2021-2-6-12