## Wikipedia - Chimica mole

https://doi.org/10.1351/goldbook.M03980
The mole, symbol mol, is the SI unit of @A00297@. One mole contains exactly $$6.022\ 140\ 76 \times 10^{23}$$ elementary entities. This number is the fixed numerical value of the @A00543@, $$N_{\text{A}}$$, when expressed in the unit $$\text{mol}^{\text{-1}}$$ and is called the Avogadro number.
The @A00297@, symbol $$n$$, of a system is a measure of the number of specified elementary entities. An elementary entity may be an atom, a molecule, an ion, an electron, any other particle or specified group of particles.
Note:
The formulation of this definition was agreed upon by the 26th CGPM in November 2018 with effect from 20 May 2019.
Source:
BIPM, The International System of Units, SI Brochure, 9th ed. (2019) [Terms] [Book]