Azobenzene is a chemical compound composed of two phenyl rings linked by a N=N

Azo compound

Azo compounds are compounds bearing the functional group R-N=N-R', in which R and R' can be either aryl or alkyl. IUPAC defines azo compounds as: "Derivatives of diazene , HN=NH, wherein both hydrogens are substituted by hydrocarbyl groups, e.g. PhN=NPh azobenzene or diphenyldiazene." The more...

 double bond

Double bond

A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that between two carbon atoms, can be found in alkenes. Many types of double bonds between two different elements exist, for example in...

. It is the best known example of an azo compound

Azo compound

Azo compounds are compounds bearing the functional group R-N=N-R', in which R and R' can be either aryl or alkyl. IUPAC defines azo compounds as: "Derivatives of diazene , HN=NH, wherein both hydrogens are substituted by hydrocarbyl groups, e.g. PhN=NPh azobenzene or diphenyldiazene." The more...

. The term 'azobenzene' or simply 'azo' is often used to refer to a wide class of molecule

Molecule

A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

s that share the core azobenzene structure, with different chemical functional groups extending from the phenyl rings. These azo compounds are considered as derivatives of diazene

Diazene

Diazene, also called diimine or diimide, is a compound having the formula 2. It exists as two geometric isomers, E and Z. Diazene is also the parent member of the entire class of azo compounds with the formula 2, where R is an organyl group...

 (diimide), and are sometimes referred to as 'diazenes'.