Fig. 1: Conceptual pressure-temperature-concentration phase diagram for a binary solution of water and a generic salt-like solute with only one solute-bearing solid phase.
From: On the equilibrium limit of liquid stability in pressurized aqueous systems
The shaded green region shows the solubility surface of the solute. The eutectic at ambient pressure is marked by the magenta circle (e), the pressure-dependent eutectic curve is marked by the thick magenta line, and the cenotectic point (κ) is marked as a magenta star. \({m}_{e}\) marks the brine concentration at the 0.1 MPa eutectic, and \({m}_{{\kappa }}\) marks the brine concentration at the cenotectic point. \({P}_{{\kappa }},\,{T}_{{\kappa }}\) mark the pressure and temperature of the cenotectic point, which we measure in this work. Isochoric freezing/melting of brine samples of concentration \({m}_{e}\) generally follows the pressure-temperature trajectory marked by the magenta eutectic curve between points (e) and (κ), and the cenotectic point can be identified by the change in the direction of the P-T slope of this curve.
