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.
Lithium (Li) appears to be the only alkali metal able to form a nitride, although all the alkaline-earth metals form nitrides with the formula M3N2. These compounds, which can be considered to consist of metal cations and N anions, undergo hydrolysis (reaction with water) to produce ammonia and the metal hydroxide.