Criegee intermediate

These chemicals may react with sulfur dioxide and nitrogen oxides in the Earth's atmosphere, and are implicated in the formation of aerosols, which are an important factor in controlling global climate.

[7] Criegee intermediates are formed by the gas-phase reactions of alkenes and ozone in the Earth's atmosphere.

[8] The alkene ozonolysis reaction is extremely exothermic, releasing about 50 kilocalories per mole (210 kJ/mol) of excess energy.

Therefore, the Criegee intermediates are formed with a large amount of internal energy.

[8] When Criegee intermediates are formed, some portion of them will undergo prompt unimolecular decay, producing OH radicals and other products.

Criegee zwitterion
Ozone reacts with an alkene to form a carbonyl and a carbonyl oxide, known as a Criegee intermediate.