Title: relative molecular mass
Long Title: IUPAC Gold Book - relative molecular mass
DOI: 10.1351/goldbook.R05271
Status: current
Index: quantity

Definition
Ratio of the mass of a molecule to the unified atomic mass unit. Sometimes called the 'molecular weight' or relative molar mass.

Related Terms
- relative molar mass: https://goldbook.iupac.org//terms/view/R05270
- unified atomic mass unit: https://goldbook.iupac.org//terms/view/U06554

Sources
- Green Book, 2nd ed., p. 41 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)
- PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 990 (https://doi.org/10.1351/pac199668040957)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/R05271/html
- json: https://goldbook.iupac.org/terms/view/R05271/json
- xml: https://goldbook.iupac.org/terms/view/R05271/xml

Citation: Citation: 'relative molecular 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.R05271
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Accessed: 2026-04-19T04:10:22+00:00