Title: allotropic transition
Long Title: IUPAC Gold Book - allotropic transition
DOI: 10.1351/goldbook.A00244
Status: current

Definition
A transition of a pure element, at a defined temperature and pressure, from one crystal structure to another which contains the same atoms but which has different properties. Examples: The transition of graphite to diamond, that of body-centred-cubic iron to face-centred-cubic iron, and the transition of orthorhombic sulfur to monoclinic sulfur.

Related Terms
- diamond: https://goldbook.iupac.org/terms/view/D01671
- graphite: https://goldbook.iupac.org/terms/view/G02684

Source
- PAC, 1994, 66, 577. 'Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)' on page 579 (https://doi.org/10.1351/pac199466030577)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/A00244/html
- json: https://goldbook.iupac.org/terms/view/A00244/json
- xml: https://goldbook.iupac.org/terms/view/A00244/xml

Citation: Citation: 'allotropic transition' 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.A00244
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Accessed: 2026-05-14T21:04:00+00:00