Cell notation (cell diagram)

A galvanic cell is shown by a short-hand diagram: anode on the left, cathode on the right, a single vertical line for each phase boundary and a double vertical line for the salt bridge:

Zn(s) | Zn²⁺(aq) || Cu²⁺(aq) | Cu(s)

For a reaction such as Ni²⁺ + Fe → Ni + Fe²⁺ the iron is oxidised, so the diagram is Fe(s) | Fe²⁺(aq) || Ni²⁺(aq) | Ni(s): iron is the anode (negative), nickel is the cathode (positive), electrons flow in the wire from iron to nickel and conventional current flows from nickel to iron.