- This article is about the aryl organic functional group. For the biological gene, see Aryl hydrocarbon receptor. For the fleshy covering of certain seeds, see aril.
In the context of organic molecules, aryl refers to any functional group or substituent derived from a simple aromatic ring. There are more specific terms, such as phenyl, to describe unsubstituted aryl groups and subsets of aryl groups (as well as arbitrarily substituted groups: see IUPAC nomenclature), but "aryl" is used for the sake of abbreviation or generalization.
The simplest 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).
Biaryls may display axial chirality.