(From the German mol, short for molekulargewicht) The basic unit of amount of substance in the International System of units, defined by the Conférence Générale des Poids et Mesures in 1971 to be the quantity of a substance which contains as many specified elementary entities as there are atoms in 0.012 kilograms of carbon-12. One mole of a substance contains 6.02214 × 1023 elementary entities (Avogadro's number).

One mole of a chemical substance has a weight in grams numerically equal to its molecular weight. One mole of an ideal gas at standard temperature and pressure is 22.414 litres.

Symbol: mol