The Avogadro constant, \(N_{\text{A}} = 6.022\ 140\ 76 \times 10^{23}\ \text{mol}^{-1}\), is a proportionality constant between the quantity @A00297@ (\(n\), with unit mole) and the quantity for counting @N04266@ (\(N\) with unit one, symbol 1), \(N = N_{\text{A}}\ n\).
  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 \(6.022\ 140\ 76 \times 10^{23}\ \text{mol}^{-1}\).
  2. The Avogadro number is the exact numerical value of the Avogadro constant, \(6.022\ 140\ 76 \times 10^{23}\)
  3. While the symbol \(N_{\text{A}}\) is used to honour Amedeo Avogadro, the symbol \(L\) is used in honour of Josef Loschmidt.
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. [Terms] [Book]