Title: polymorph
Long Title: IUPAC Gold Book - polymorph
DOI: 10.1351/goldbook.15225
Status: current

Definition
Solid material that exists at least in two different molecular arrangements, i.e., distinctly different crystal species.

Notes
1) The differences between polymorphs disappear in solution or in the vapor phase.
2) Solubility, melting point, density, crystal shape, crystal structure, and some other physical properties often differ from one polymorph to the other.

Related Term
- crystal: https://goldbook.iupac.org/terms/view/15166

Source
- PAC, 2009, 81, 971. 'Glossary of terms related to pharmaceutics (IUPAC Recommendations 2009)' on page 994 (https://doi.org/10.1351/PAC-REC-04-10-14)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/15225/html
- json: https://goldbook.iupac.org/terms/view/15225/json
- xml: https://goldbook.iupac.org/terms/view/15225/xml

Citation: Citation: 'polymorph' 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.15225
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.
Collection: If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .
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.
Accessed: 2026-05-13T19:33:10+00:00