Organic chemistry is the branch of chemistry concerned with the study of those carbon-containing molecules known as organic compounds, which are based upon long chains or rings of carbon atoms. Organic chemistry is the basis of most biochemistry, the study of the chemical processes which take place in living organisms.

Some of the classes of substances studied in organic chemistry include aliphatic compounds, chains of carbon which may be modified by functional groups; aromatic hydrocarbons, compounds containing one or more benzene rings; heterocyclic compounds, those which include non-carbon atoms as part of a ring structure; and polymers, which are long chains of repeating groups.

Organic chemistry as a science is generally agreed to have started with Friedrich Woehler's synthesis of the organic, biologically significant compound urea from inorganic starting materials in 1828.

Aliphatic compounds

Hydrocarbons - Alkanea - Alkenes - Dienes or Alkadienes - Alkynes - Halogenoalkanes - Alcohols - Ethers - Aldehydes - Ketones - Carboxylic acids - Esters - Carbohydrates - Alicyclic compounds - Lipids

Aromatic compounds


Heterocyclic compounds



Organic nomenclature - Chemical formula - Structural formula - Skeletal formula - Organic reaction

Characteristics of organic substances

The reason that there are so many carbon compounds is that carbon has the ability to form many carbon chains of different lengths, and rings of different sizes (catenation). A lot of carbon compounds are extremely sensitive to heat, and generally decompose below 300'C. They tend not to be so soluble in water compared to many inorganic salts. In contrast to such salts, they tend to be much more soluble in organic solvents such as ether or alcohol. Organic compounds are covalently bonded.