Term: syntectic reaction
https://doi.org/10.1351/goldbook.S06232

Definition:
A reversible reaction that involves the conversion of two liquid phases, l' and l'', into a solid phase α on cooling: \[\text{l}^{'}+\text{l}^{''}\rightleftharpoons \unicode[Times]{x3B1} \] The maximum temperature at which this reaction can occur is the congruent melting point of the solid phase. Example: The conversion of co-existing K-rich and Zn-rich phases in the K-Zn system to form an intermediate solid phase KZn13.

Related Terms:
1) melting (http://doi.org/10.1351/goldbook.M03821).

Source: PAC, 1994, 66, 577. 'Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)' on page 592 (https://doi.org/10.1351/pac199466030577)

Citation: 'syntectic reaction' 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.S06232

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.