Why are radicals unsplit in chemical reactions?
In chemistry, a radical (more precisely, a free radical) is an atom, molecule, or ion that has an unpaired valence electron. With some exceptions, these unpaired electrons make free radicals highly chemically reactive. Many free radicals spontaneously dimerize. Most organic radicals have short lifetimes.
A notable example of a free radical is the hydroxyl radical (HO•), a molecule that has one unpaired electron on the oxygen atom. Two other examples are triplet oxygen and triplet carbene (:CH
2) which have two unpaired electrons.