Ozone is a molecule made up of 3 oxygen atoms. Shown below is one of four resonant forms of the molecule.
Ozone is a colorless gas at room temperature, and has a peculiar, pungent odor often observed during electrical storms after lightning dicharges. Ozone supports combustion and is the fourth most powerful oxidizing agent known (behind F2, F2O, and free radical oxygen atoms).
Typical functional groups readily oxidized by O3 are -SH, =S, -NH2, =NH, -OH(phenolic), and -CHO.
The mechanism of disinfection with O3 is directly related to the following reaction:
O3 -------> O2 + O
The nascent oxygen produces a high-energy oxidation via a free radical mechanism. Bacterial cells viewed after ozonation appear to have been exploded. No rigid structural features were able to withstand the oxidation process. Ozonated cells appear as a splash of gelatinous material.