Title: molar mass
Long Title: IUPAC Gold Book - molar mass
DOI: 10.1351/goldbook.12214
Status: current

Definition
Mass divided by amount of substance.

Notes
1) In the present context, "amount of substance" is the number of molecules divided by the Avogadro constant, \(N_{\rm{A}} [= \pu{6.02214076E23 mol-1}]\).
2) If the unit \(\pu{g mol-1}\) unit is used, the numerical values of molar mass, relative molecular mass and relative molar mass are equal.
3) The term "molar" may also be used for entities consisting of more than one molecule, such as complexes, aggregates, micelles, etc.

Source
- PAC, 2015, 87, 71. 'Definitions of terms relating to individual macromolecules, macromolecular assemblies, polymer solutions, and amorphous bulk polymers (IUPAC Recommendations 2014)' on page 82 (https://doi.org/10.1515/pac-2013-0201)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/12214/html
- json: https://goldbook.iupac.org/terms/view/12214/json
- xml: https://goldbook.iupac.org/terms/view/12214/xml

Citation: Citation: 'molar mass' 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.12214
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Accessed: 2026-07-15T00:03:31+00:00