A colorless gaseous substance (O&?;) obtained (as by the silent discharge of electricity in oxygen) as an allotropic form of oxygen, containing three atoms in the molecule. It is a streng oxidizer, and probably exists in the air, though by he ordinary tests it is liable to be confused with certain other substances, as hydrogen dioxide, or certain oxides of nitrogen. It derives its name from its peculiar odor, which resembles that of weak chlorine.
- An unstable, poisonous allotrope of oxygen, O3, that is formed naturally in the ozone layer from atmospheric oxygen by electric discharge or exposure to ultraviolet radiation, also produced in the lower atmosphere by the photochemical reaction of certain pollutants. It is a highly reactive oxidizing agent used to deodorize air, purify water, and treat industrial wastes.
- Informal Fresh, pure air.