The use of molten CaCl is important because this molten salt can dissolve and transport the "O" ions to the anode to be discharged. The anode reaction depends on the material of the anode. Depending on the system it is possible to produce either CO or CO or a mixture at the carbon anode:
However, if an inert anode is used, such as that of high density SnO, the discharge of the O ions leads to the evolution of oxygen gas. However the use of an inert anode has disadvantages. Firstly, when the concentration of CaO is low, Cl evolution at the anode becomes more favourable. In addition, when compared to a carbon anode, more energy is required to achieve the same reduced phase at the cathode. Inert anodes suffer from stability issues.