The mole (symbol mol) is a unit of measurement, the base unit in the International System of Units (SI) for amount of substance. It is an SI base quantity proportional to the number of elementary entities of a substance.
One mole is an aggregate of exactly 6.02214076×1023 elementary entities (approximately 602 sextillion or 602 billion times a trillion), which can be atoms, molecules, ions, ion pairs, or other particles. The number of particles in a mole is the Avogadro number (symbol N0) and the numerical value of the Avogadro constant (symbol NA) has units of mol−1.
The relationship between the mole, Avogadro number, and Avogadro constant can be expressed in the following equation:
1 mol = N0 / NA= 6.02214076×1023 = NA