The calomel electrode (CEc) is a reference electrode based on the reaction between elemental mercury and mercury(I) chloride. The aqueous phase in contact with the mercury and the mercury(I) chloride (Hg₂Cl₂, “calomel”) is a saturated solution of potassium chloride in water. The electrode is linked via a porous frit to the solution in which the other electrode is immersed. This porous frit makes liquid junction. Calomel electrode (CEc) is designed for measurements with thermostated cell TC4, TC5, TC6, TC9.