In
organic chemistry,
hydrocarbons (
compounds composed of
carbon and
hydrogen) are divided into two classes:
aromatic compounds and
aliphatic compounds (; G.
aleiphar, fat, oil) also known as non-aromatic compounds. Aromatic compounds contain an aromatic-ring configuration of atoms, such as
benzene, whereas aliphatic compounds do not. Aliphatic compounds can be saturated, like
hexane, or unsaturated, like
hexene.