Avogadro constant

symbols: $N_{\rm{A}}$, $L$
https://doi.org/10.1351/goldbook.A00543
The Avogadro constant, \(N_{\rm{A}} = \pu{6.02214076E23 mol-1}\), is a proportionality constant between the quantity amount of substance (\(n\), with unit mole) and the quantity for counting entities (\(N\) with unit one, symbol 1), \(N = N_{\rm{A}}\ n\).
Notes:
  1. In the revision of the International System of Units (SI) of 2019 the Avogadro constant became one of the seven defining constants with the exact value \(\pu{6.02214076E23 mol-1}\).
  2. The Avogadro number is the exact numerical value of the Avogadro constant, \(\pu{6.02214076E23}\)
  3. While the symbol \(N_{\rm{A}}\) is used to honour Amedeo Avogadro, the symbol \(L\) is used in honour of Josef Loschmidt.
Sources:
BIPM, Le Système international d’unités (SI), SI Brochure, 9e ed. (2019), p. 17 [Terms] [Book]
BIPM, The International System of Units, SI Brochure, 9th ed. (2019), p. 129 [Terms] [Book]
Green Book, 3rd ed., p. 129 [Terms] [Book]
Citation: 'Avogadro constant' 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.A00543 RIS BibTex EndNote
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