Term: unified atomic mass unit
https://doi.org/10.1351/goldbook.U06554

Definition:
Non-SI unit of mass (equal to the atomic mass constant), defined as one twelfth of the mass of a carbon-12 atom in its ground state and used to express masses of atomic particles, u ≈ 1.660 5402 10 x 10E-27 kg.

Related Terms:
1) atomic mass constant (http://doi.org/10.1351/goldbook.A00497).
2) ground state (http://doi.org/10.1351/goldbook.G02704).

Source: Green Book, 2nd ed., p. 75 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)

Citation: 'unified atomic mass unit' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.U06554

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