Commutator (electric) A commutator is a moving part of a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine.
The word equation that would represent the formation of lithium oxide from lithium metal and oxygen is: lithium + oxygen to lithium oxide. In chemical symbols, the balanced chemical equation is expressed as: Li + O2 = Li2O.
The ionic oxides are characterized by the presence of the oxide ion, O2-, that like the H+ ion, cannot exist alone in aqueous solution. The reaction between the oxide and a water molecule is shown below: The 2- charged oxide attacks and forms a bond with a partially positive hydrogen atom of the water molecule.