In organic chemistry, benzoyl (, ) is the functional group with the formula and structure . It can be viewed as benzaldehyde missing one hydrogen. The benzoyl group has a mass of 105 amu.
The term "benzoyl" should not be confused with benzyl, which has the formula . The benzoyl group is given the symbol "Bz" whereas benzyl is commonly abbreviated "Bn".
Benzoyl chloride is a favored source of benzoyl groups, being used to prepare benzoyl ketones, benzamides (benzoyl amides), and benzoate esters. The source of many naturally occurring benzoyl compounds is the thioester benzoyl-CoA. Irradiation of benzil generates benzoyl radicals, which have the formula PhCO.
Many ketones contain the benzoyl group. They have the formula C<sub>6</sub>H<sub>5</sub>COâÂÂR, an important example being benzophenone.
Benzoyl esters and amides are common in organic chemistry. The esters are used as a protecting groups in organic synthesis, which can be easily removed by hydrolysis in dilute basic solution. Benzoyl-ò-<small>D</small>-glucoside is a natural substance that can be found in Pteris ensiformis.