The paper analyzes the crystallizing phases in the ternary reciprocal system Ca,Ba | | F,Cl, describes the chemical interaction of ion exchange reactions and complexation reactions. The system is partitioned into simplices using graph theory. A tree of phases of the system has been constructed, on the basis of which a prediction of the number and composition of crystallizing phases in stable elements has been made. A 3D model of the phase complex of the Ca,Ba | | F,Cl system was built using the KOMPAS 3D v21 software. On the stable CaF2–BaCl2 diagonal, the presence of a quasi-binary eutectic and the stability of the crystallizing phases were confirmed by thermogravimetry and XRD methods.