Title: macromolecule
Long Title: IUPAC Gold Book - macromolecule
DOI: 10.1351/goldbook.M03667
Status: current

Definition
A molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass.

Notes
1) In many cases, especially for synthetic polymers, a molecule can be regarded as having a high relative molecular mass if the addition or removal of one or a few of the units has a negligible effect on the molecular properties. This statement fails in the case of certain macromolecules for which the properties may be critically dependent on fine details of the molecular structure.
2) If a part or the whole of the molecule has a high relative molecular mass and essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass, it may be described as either macromolecular or polymeric, or by polymer used adjectivally.

Related Term
- relative molecular mass: https://goldbook.iupac.org//terms/view/R05271

Source
- PAC, 1996, 68, 2287. 'Glossary of basic terms in polymer science (IUPAC Recommendations 1996)' on page 2289 (https://doi.org/10.1351/pac199668122287)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/M03667/html
- json: https://goldbook.iupac.org/terms/view/M03667/json
- xml: https://goldbook.iupac.org/terms/view/M03667/xml

Citation: Citation: 'macromolecule' 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.M03667
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Accessed: 2026-06-19T20:28:18+00:00