In the Criegee mechanism, this compound reacts through a 1,3-dipolar cyclo·addition to cleave double bonds in alkenes. Sydney Chapman discovered the process by which this continuously regenerates. Discovered by Christian Friedrich Schönbein in 1840, 
In the Criegee mechanism, this compound reacts through a 1,3-dipolar cyclo·addition to cleave double bonds in alkenes. Sydney Chapman discovered the process by which this continuously regenerates. Discovered by Christian Friedrich Schönbein in 1840, it gives a thunderstorm its distinctive smell. It converts electromagnetic radiation into heat energy in a reaction catalyzed by hydroxyl and chloro·fluoro·carbons. At ground level, it is a pollutant and respiratory irritant, but it occurs in high concentrations in the stratosphere, where it absorbs UV rays. For 10 points, name this triatomic form of oxygen, which has a namesake "layer" in the atmosphere.
In the Criegee mechanism, this compound reacts through a 1,3-dipolar cyclo·addition to cleave double bonds in alkenes.
{ozone} (prompt on {O3} until “{triatomic}” is read)