In organic chemistry, a radical (or free radical) is a particle that has at least one unpaired electron. Because of this unpaired electron, radicals are usually unstable and very reactive.
How radicals form
They are usually created when a chemical bond breaks in such a way that each atom takes away one electron. This process often happens under heat, light, or with special initiators.
Types of carbon radicals
- Methyl radical – the simplest radical with only one carbon.
- Primary radical – the unpaired electron is on a carbon attached to one other carbon.
- Secondary radical – the unpaired electron is on a carbon attached to two other carbons.
- Tertiary radical – the unpaired electron is on a carbon attached to three other carbons.
Stability of radicals
Tertiary radicals are more stable than secondary, which are more stable than primary and methyl. This happens because nearby atoms help spread out or “delocalize” the unpaired electron, making the radical less reactive.
Why radicals matter
Radicals are important in many chemical and biological processes:
- They are involved in reactions of alkanes with halogens.
- They are used in polymer formation such as making plastics.
- They play a role in combustion (burning of fuels).
- In living organisms, radicals can be harmful and cause cell damage, which is why antioxidants are important.