Resolution 3 of the 14th CGPM (1971)

SI unit of amount of substance (mole)

The 14th Conférence Générale des Poids et Mesures (CGPM),

considering the advice of the International Union of Pure and Applied Physics, of the International Union of Pure and Applied Chemistry, and of the International Organization for Standardization, concerning the need to define a unit of amount of substance,


  1. The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12; its symbol is "mol".
  2. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.
  3. The mole is a base unit of the Système International d'Unités.

DOI : 10.59161/CGPM1971RES3E

The reader should note that the official version of this Resolution is the French text


At its 1980 meeting, the CIPM approved the report of the 7th meeting of the CCU (1980) specifying that, in this definition, it is understood that unbound atoms of carbon 12, at rest and in their ground state, are referred to.

This definition of the mole was abrogated in 2018 by the 26th CGPM (Resolution 1), which became effective in 2019.

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