Aryl

In the context of organic molecules, aryl is any functional group or substituent derived from an aromatic ring, usually an aromatic hydrocarbon, be it phenyl, naphthyl, thienyl, indolyl, etc. (see Chemical nomenclature). "Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used as a placeholder for the aryl group in chemical structure diagrams.

A simple aryl group is phenyl, C₆H₅; it is derived from benzene. The tolyl group, CH₃C₆H₄, is derived from toluene (methylbenzene). The xylyl group, (CH₃)₂C₆H₃, is derived from xylene (dimethylbenzene), while the naphthyl group, C₁₀H₇, is derived from naphthalene.

Arylation is a chemical process in which an aryl group is attached to a substituent.