Term: miscibility gap
https://doi.org/10.1351/goldbook.MT07270

Definition:
Area within the coexistence curve of an isobaric phase diagram (temperature vs composition) or an isothermal phase diagram (pressure vs composition).

Note: A @MT07230@ gap is observed at temperatures below an @UT07280@ (UCST) or above the lower @C01401@ (LCST). Its location depends on pressure. In the @MT07230@ gap, there are at least two phases coexisting.

Related Terms:
1) miscibility (http://doi.org/10.1351/goldbook.MT07230).
2) upper critical solution temperature (http://doi.org/10.1351/goldbook.UT07280).
3) critical solution temperature (http://doi.org/10.1351/goldbook.C01401).

Source: PAC, 2004, 76, 1985. 'Definition of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC Recommendations 2004)' on page 1996 (https://doi.org/10.1351/pac200476111985)

Citation: 'miscibility gap' 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.MT07270

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