SI base unit: mole (mol)
The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly
The amount of substance, 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.
This definition implies the exact relation NA =
![](/documents/20126/42149531/SI-equation-mol-EN.jpg/6899f624-d358-e688-0706-8d76e578a39f?t=1594242411819)
The effect of this definition is that the mole is the amount of substance of a system that contains
See:
SI Brochure - Appendix 2
SI Brochure - excerpts from Appendix 4