Ozone ( O3 symbol ) is a gas from the characteristic garlic-like smell, whose molecules consist of three oxygen atoms. It can not therefore be stored, and must be produced at the time of use.

It has a characteristic pungent odor-the same that sometimes accompanies thunderstorms, due precisely to ozone produced by lightning. The resulting compounds are called ozone ozonide.

Ozone is known primarily for its role in the ecological balance of the earth . In fact, it absorbs most of the ultraviolet radiation coming from the sun, preventing them from reaching directly to the earth’s surface.