In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure C6H5CH2–. Benzyl features a benzene ring attached to a CH2 group.
In IUPAC nomenclature the prefix benzyl refers to a C6H5CH2 substituent, for example benzyl chloride or benzyl benzoate. Benzyl is not to be confused with phenyl with the formula C6H5. The term benzylic is used to describe the position of the first carbon bonded to a benzene or other aromatic ring. For example, the molecule, is referred to as a "benzylic" carbocation. The benzyl free radical has the formula C
6H
5CH•
2. The benzylium carbocation has the formula C
6H
5CH+
2; the carbanion has the formula C
6H
5CH−
2. None of these species can be formed in significant amounts under normal conditions, but they are useful referents for discussion of reaction mechanisms.