Acyl
An acyl group is a functional group derived by the removal of one or more hydroxyl groups from an oxoacid, including inorganic acids.
In organic chemistry, the acyl group is usually derived from a carboxylic acid (IUPAC name: alkanoyl). Therefore, it has the formula RCO-, where R represents an alkyl group that is attached to the CO group with a single bond. Although the term is almost always applied to organic compounds, acyl groups can in principle be derived from other types of acids such as sulfonic acids, phosphonic acids. In the most common arrangement, acyl groups are attached to a larger molecular fragment, in which case the carbon and oxygen atoms are linked by a double bond.
Read more about Acyl: Acyl Compounds, Acylium Cations, Anions, and Radicals, In Biochemistry, In Organometallic Chemistry and Catalysis, Nomenclature, Acyl Species