Binary phase diagrams are of scientific and practical importance in material science. In particular, they represent the stability regions of solid and liquid phases  formed by the two components. The experimental construction of phase diagrams requires accurate and well equilibrated thermo-physical measurements to obtain the equilibrium thermodynamic conditions. Hence, it took the scientific community many decades to map the complex phase space of thousands of binary systems at ambient conditions.

Pressure affects phase diagrams both by altering the interactions, which control the nature of the diagram, and by the emergence of new phases and phase boundaries. However, measuring accurate thermophysical properties under pressure and temperature is challenging Therefore, combination of experimental measurements and thermodynamic modelling is useful in order to achieve a full understanding of the pressure evolution of binary systems.

In the present contribution we study the pressure evolution of the isomorphous Bi-Sb binary system by , XRD measurements in diamond anvil cell (DAC) and advanced thermodynamic model.

By incorporating pressure into the model and validating the results against accurate measurements, we are able to predict the pressure dependence of binary phase diagrams; including changes in the nature of the diagram, and the evolution of interaction parameters with pressure. These results will allow in the future a comparison with results of advanced modelling of binary systems via calculation of interaction parameters of the system’s constituents.