15320 IUPAC Gold Book - coexistence curve 10.1351/goldbook.15320 15320 current synonyms: binodal curve, conodal curve 1 Boundary of stable phase separation (limits of solubility) in a liquid or solid system of two or more components. The locus of the compositions of two co-existing phases on a phase diagram. 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. binary system https://goldbook.iupac.org//terms/view/15316 components https://goldbook.iupac.org//terms/view/16268 conjugate phases https://goldbook.iupac.org//terms/view/15321 higher-order systems https://goldbook.iupac.org//terms/view/15332 mole fraction https://goldbook.iupac.org//terms/view/15376 ternary https://goldbook.iupac.org//terms/view/15366 ternary diagram https://goldbook.iupac.org//terms/view/15365 PAC, 2008, 80, 233. 'Glossary of terms related to solubility (IUPAC Recommendations 2008)' on page 241 (https://doi.org/10.1351/pac200880020233) https://goldbook.iupac.org/terms/view/15320/html https://goldbook.iupac.org/terms/view/15320/json https://goldbook.iupac.org/terms/view/15320/plain Citation: 'coexistence curve' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.15320 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-07-28T05:08:01+00:00