Phenyl Group - Nomenclature

Nomenclature

Phenyl groups are often represented by the symbol Ph or, archaically, Φ. Benzene is sometimes denoted as PhH. Phenyl groups are generally attached to other atoms or groups. For example, triphenylmethane (Ph₃CH) has three phenyl groups attached to the same carbon centre. Many or even most phenyl compounds are not described with the term "phenyl". For example the chloro derivative C₆H₅Cl is normally called chlorobenzene, although it could be called phenyl chloride. In special (and rare) cases, isolated phenyl groups are detected: the phenyl anion (C₆H₅–), the phenyl cation (C₆H₅+), and the phenyl radical (C₆H₅·).

Although Ph and phenyl uniquely denote C₆H₅, substituted derivatives also are described using the phenyl terminology. For example, O₂NC₆H₄ is nitrophenyl (of which three isomers are possible) and F₅C₆ is pentafluorophenyl.