coexistence curve

synonyms: binodal curve, conodal curve
https://doi.org/10.1351/goldbook.15320
Boundary of stable phase separation (limits of solubility) in a liquid or solid system of two or more components.
Notes:
  1. The locus of the compositions of two co-existing phases on a phase diagram.
  2. In a binary system, a plot of experimental variables such as temperature or pressure, or of theoretical variables such as Gibbs energy, against mole fraction displays the coexistence curve. In ternary or higher-order systems, coexistence curves are displayed on a plot of composition at constant temperature or pressure, usually on a ternary diagram.
Source:
PAC, 2008, 80, 233. (Glossary of terms related to solubility (IUPAC Recommendations 2008)) on page 241 [Terms] [Paper]