anion

Ion carrying a negative charge. An anion is formed from an atom by the gain of electrons, a process known as ionic bonding. Non-metallic elements form anions. During electrolysis, anions in the electrolyte move towards the anode (positive electrode).

An electrolyte, such as the salt zinc chloride (ZnCl₂), is dissociated in aqueous solution or in the molten state into doubly charged Zn²⁺ cations and singly-charged Cl^- anions. During electrolysis, the zinc cations flow to the cathode (to become discharged and liberate zinc metal) and the chloride anions flow to the anode (to become discharged and form chlorine gas).