Cell notation in chemistry is a shorthand way of expressing a certain reaction in an electrochemical cell. The cell anode and cathode (half-cells) are separated by two bars or slashes representing a salt bridge, with the anode on the left and cathode on the right.[1][2] Individual solid, liquid or aqueous phases within each half-cell are separated by a single bar. Concentrations of dissolved species, in each phase written in parentheses and the state of each phase (usually s (solid), l (liquid), g (gas) or aq. (aqueous solution)) is included in a subscript after the species name.
This illustrates a Silver (Ag) - Cadmium (Cd) cell defined by the following half reactions, with 0.010M Cadmium chloride (CdCl2) as electrolyte. The Mercury (Hg) does nothing except act as an amalgam.
The Zinc-Hydrogen Cell
Some gas electrodes