An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered inorganic. The division between "organic" and "inorganic" carbon compounds while "useful in organizing the vast subject of chemistry...is somewhat arbitrary".

Organic chemistry is the science concerned with all aspects of organic compounds. Organic synthesis is the methodology of their preparation.

History

The name "organic" is historical, dating back to the 19th century, when it was believed that organic compounds could only be synthesized in living organisms through vis vitalis - the "life-force". The theory that organic compounds were fundamentally different from those that were "inorganic", that is, not synthesized through a life-force, came under question in 1824 when Friedrich Wöhler synthesized oxalic acid, a known compound made by living organisms, from cyanogen. A more famous experiment of 1828 involved the synthesis of urea by Wöhler in the Wöhler synthesis. Urea was well-known as an "organic" compound by definition of its known occurrence only in the urine of living organisms, but Wöhler produced urea from the inorganic salts potassium cyanate and ammonium sulfate,without the action of a living organism.

Notably, neither oxalic acid nor urea itself, the two historical prototypical organic compounds made by Wöhler, contain a C-H bond, even though this criterion has sometimes been used as a chemical definition of organic compounds. This may serve to illustrate the residual imperfect match which still exists between historical and attempted chemical definitions of terms. However, the kinds of carbon compounds that are still traditionally considered inorganic are those that were considered inorganic before Wöhler's time; that is, those which came from "inorganic" (i.e., lifeless) sources such as certain carbonate minerals.Spencer L. Seager, Michael R. Slabaugh. Chemistry for Today: general, organic, and biochemistry. Thomson Brooks/Cole, 2004, p. 342. ISBN 053439969X However, the mineral "coal," which is derived from plants, is usually considered to be organic under this loose historical definition (as would other so-called fossil fuels). Such a definition, however, would not include the mineral diamond.

Classification

See Organic chemistry#Classification of organic substances

Organic compounds may be classified in a variety of ways. One major distinction is between natural and synthetic compounds. They may also be distinguished by the presence of additional atoms of further elements, so-called heteroatoms. Organometallic compounds constitute a further subsection, characterized by covalent bonds between organic carbon and a metal.