20.5 : 自由基的形成：夺取

When a radical abstracts a species from a compound, it leads to the formation of a new radical. If the species abstracted is a hydrogen atom, it is known as hydrogen abstraction.

However, this is different from the proton transfer process. A transfer of protons is ionic, where only the nucleus of the hydrogen atom undergoes relocation.

In the hydrogen abstraction method, the whole hydrogen atom—the proton and the electron—is moved across.

Similar to hydrogen abstraction is halogen abstraction. Here, instead of a hydrogen atom, a halogen atom is abstracted to produce a new radical.