A

Aromatic Hydrocarbons

CₙH₂ₙ₋₆; benzene: C₆H₆
Quick Reference
Formula / NotationCₙH₂ₙ₋₆; benzene: C₆H₆
Also Known AsArenes, aromatic compounds, benzenoid hydrocarbons, PAHs (polycyclic)

What is Aromatic Hydrocarbons?

Aromatic hydrocarbons are cyclic organic compounds containing conjugated pi electrons that satisfy Hückel's rule (4n+2 π electrons). Benzene (C₆H₆) is the prototype aromatic compound. Aromatic compounds are unusually stable due to electron delocalisation and undergo electrophilic substitution rather than addition reactions. They include benzene, toluene, naphthalene, and many biologically important molecules.

Formula & Notation

CₙH₂ₙ₋₆; benzene: C₆H₆

Other Names / Synonyms: Arenes, aromatic compounds, benzenoid hydrocarbons, PAHs (polycyclic)

Properties & Characteristics

Aromatic hydrocarbons are cyclic, planar organic compounds containing delocalised π electron systems that satisfy Hückel's rule (4n+2 π electrons, where n is a non-negative integer). They exhibit unusual stability (resonance energy) relative to hypothetical non-delocalised structures. Benzene (C₆H₆) is the archetypal aromatic compound, with six π electrons and a bond length intermediate between single and double bonds (140 pm).

Uses & Applications

Benzene, toluene, and xylene (BTX) are industrial feedstocks for plastics, synthetic fibres, dyes, and pharmaceuticals. Naphthalene is used in mothballs and dye synthesis. Aromatic rings are ubiquitous in drug molecules, natural products, and polymers such as polystyrene and Kevlar.

Safety Information

Many aromatic hydrocarbons are toxic, carcinogenic, or mutagenic. Benzene is a Class 1 IARC carcinogen (causes leukaemia). Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic combustion byproducts. Always work with aromatic solvents in a fume hood with appropriate PPE.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Aromatic Hydrocarbons
Formula CₙH₂ₙ₋₆; benzene: C₆H₆
Synonyms Arenes, aromatic compounds, benzenoid hydrocarbons, PAHs (polycyclic)

Frequently Asked Questions

Aromatic hydrocarbons are cyclic organic compounds containing conjugated pi electrons that satisfy Hückel's rule (4n+2 π electrons). Benzene (C₆H₆) is the prototype aromatic compound. Aromatic compounds are unusually stable due to electron delocalisation and undergo electrophilic substitution rather than addition reactions. They include benzene, toluene, naphthalene, and many biologically important molecules.

More "A" Terms

View all "A" terms →
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z