Homolytic bond cleavage is a way in which a chemical bond breaks evenly, so that each atom involved in the bond takes one electron from the shared pair. This process produces two free radicals.
1. Definition
- In homolytic cleavage, a covalent bond splits symmetrically.
- Each atom ends up with one unpaired electron, forming a radical.
- It is different from heterolytic cleavage, where one atom takes both electrons and forms ions.
2. How it Happens
- Homolytic cleavage usually occurs when energy is supplied, such as:
- Heat
- Light (UV radiation)
- Chemical initiators
- This energy breaks the bond evenly, creating radicals.
3. Example
- When a molecule like Cl₂ is exposed to UV light, the Cl–Cl bond breaks homolytically:
- Each chlorine atom gets one electron.
- Two chlorine radicals are formed, which are highly reactive.
4. Importance in Chemistry
- Homolytic cleavage is the first step in many radical reactions, including:
- Free radical halogenation of alkanes
- Radical polymerization of alkenes
- Radical addition reactions
- It explains how free radicals are generated in both laboratory and industrial processes.
5. Key Points
- Produces two radicals.
- Requires energy input (heat, light, or chemical initiator).
- Fundamental in radical chain reactions.