The two forms of oxygen found in the atmosphere are:
- Molecular oxygen(O2)
Molecular oxygen (O2 ) is a diatomic molecule composed of two oxygen atoms held together by a covalent bond. Molecular oxygen is essential for life, as it is used for respiration by many organisms. In addition, molecular oxygen is important for combustion – especially in the combustion of fuels for energy. There is a double bond between these two atoms. Since the two oxygen atoms have eight electrons around them, the oxygen molecule is less reactive.
Ozone (O3) is a highly reactive gas composed of three oxygen atoms. It is both a natural and a human-made product that occurs in the Earth’s upper atmosphere. Ozone is also a powerful oxidising agent.
- Ozonolysis is a reaction of alkenes with ozone. Ozone can be produced in the lab using a machine called an Ozonator.
- This ozone is passed through a solution of the alkene, first producing an ozonide.
- This ozonide is subsequently reduced, giving cleavage around the double bond, with oxygen attached to each carbon from the double bond.