Term: immiscibility https://doi.org/10.1351/goldbook.IT07239 Definition: Inability of a mixture to form a single phase. Notes: 0) Immiscibility may be limited to certain ranges of temperature, pressure, and composition. 1) Immiscibility depends on the chemical structures, molar-mass distributions, and molecular architectures of the components. Source: PAC, 2004, 76, 1985. 'Definition of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC Recommendations 2004)' on page 1990 (https://doi.org/10.1351/pac200476111985) Citation: 'immiscibility' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.IT07239 License: 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. Disclaimer: 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.