Phenyl group

[1][2] Usually, a "phenyl group" is synonymous with C6H5− and is represented by the symbol Ph (archaically, Φ), or Ø. Benzene is sometimes denoted as PhH.

Higher degrees of substitution, of which the pentafluorophenyl group is an example, exist and are named according to IUPAC nomenclature.

[3] According to McMurry, "The word is derived from Greek pheno 'I bear light', commemorating the discovery of benzene by Michael Faraday in 1825 from the oily residue left by the illuminating gas used in London street lamps.

It is generally considered an inductively withdrawing group (-I), because of the higher electronegativity of sp2 carbon atoms, and a resonance donating group (+M), due to the ability of its π system to donate electron density when conjugation is possible.

These chemical shifts are influenced by aromatic ring current and may change depending on substituents.

A major product of the petrochemical industry is "BTX" consisting of benzene, toluene, and xylene - all of which are building blocks for phenyl compounds.

The polymer polystyrene is derived from a phenyl-containing monomer and owes its properties to the rigidity and hydrophobicity of the phenyl groups.

It is often said the resonance stability of phenol makes it a stronger acid than that of aliphatic alcohols such as ethanol (pKa = 10 vs. 16–18).