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Ozone (26k jpeg) was first discovered in 1839 by German scientist Christian Friedrich Schonbein. It is a pale blue, relatively unstable molecule made up of three oxygen atoms. The ozone molecule is angular, polar, and diamagnetic. Both oxygen bond lengths (1.28 angstroms) are identical. It is formed from molecular oxygen (O2) by ultraviolet and extreme ultraviolet photolysis followed by recombination of atomic oxygen (O) with O2.
It may also be formed by passing an electrical discharge through gaseous oxygen. It is characterized by a unique odor that is often noticed during electrical storms and in the vicinity of electrical equipment. In fact, the term ozone is derived from the Greek word ozein which means "to smell." The density of ozone is about 2.5 times that of O2. At -112 degrees C it condenses to a deep blue liquid. It is a powerful oxidizing agent and, as a concentrated gas or a liquid, is highly explosive.
Excess oxygen atoms, also known as free radicals, oxidize materials that they contact and are associated with the aging process.
