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.
1 Sodium and Chlorine combine to form Sodium Chloride. 2  Magnesium and Oxygen combine to form Magnesium Oxide. 3  Lithium and Nitrogen combine to form Lithium Nitride. 4  When writing the formula the number of each element must be choosen so that the total positive charge equals the total negative charge.