# Faraday constant

In chemistry and physics, the **Faraday constant** *F* is the amount of charge (in absolute value) in one mole of electrons or one mole of monovalent (singly charged) ions. Its value^{[1]} is

where *N*_{A} is Avogadro's constant and *e* is the charge of an electron.

The constant *F* must be carefully distinguished from the unit F (the faraday) which is a unit of capacitance.

The constant and the unit are named after the British physicist Michael Faraday.

Before electrons were discovered and a value for Avogadro's number was known, Faraday discovered (1833) that in electrolysis the amount of charge *F* necessary to deposit one mole of monovalent ions on an electrode (cations on the cathode, anions on the anode) is always the same, irrespective of the kind of ions. For a long time weighing the amount of silver—which in solution is the cation Ag^{+}—deposited during electrolysis was the accepted manner of measuring electric charge and electric current.