Organic compound
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An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic. The study of organic compounds is termed organic chemistry, and since it is a vast collection of chemicals (over half of all known chemical compounds), systems have been devised to classify organic compounds. A few of the compound classes based on the functional groups they carry are as follows:
Many organic compounds are also of prime importance in biochemistry:
- Antigens
- Polysaccharides, carbohydrates and sugars
- Enzymes
- Hormones
- Lipids and fatty acids
- Neurotransmitters
- Nucleic acids
- Proteins, peptides and amino acids
- Vitamins
Number crunching
A large collection of organic compounds is maintained in the Beilstein database. A cheminformatics study involving 5.9 million substances and 6.5 million reactions from this database showed that the organic compound universe consists or a core of around 200,000 molecules strongly connected to each other and a large periphery (3.6 million molecules) around it <ref>The Core and Most Useful Molecules in Organic Chemistry Kyle J. M. Bishop, Rafal Klajn, Bartosz A. Grzybowski Angewandte Chemie International Edition Volume 45, Issue 32 , Pages 5348 - 5354 2006 Template:DOI</ref>. Core and periphery are surrounded by a group of non-connected small islands containing 1.2 million molecules, a model resembling the world wide web. More key statistics:
- The core molecules (only 3.5% of the total) are involved in 35% of all reactions giving rise to 60% of all molecules.
- The average distance between two molecules in the core is 8.4 synthetic steps and 95% of all connecting reactions are fewer than 15 steps. Any molecule in the periphery can be reached by one from the core in fewer than 3 steps.
- The relative size of the core peaked in 1880 and has since then declined.
- The core contains 70% of the top 200 industrial chemicals.
- An optimised chemical inventory of 300 chemicals for a hypothetical chemical company allows the synthesis of up to 1.2 million organic compounds and contains 10 Wittig reagents, 6 Grignard reagents, 2 DNA building blocks and 18 aromatic aldehydes.
History and nomenclature
The name "organic" is an historical name, dating back to 19th century, when it was believed that organic compounds could only be synthesised 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, was disproved with the synthesis of urea, an organic compound, from potassium cyanate and ammonium sulfate by Friedrich Wöhler in the Wöhler synthesis.
The dividing line between organic and inorganic is contested and historically arbitrary; generally speaking, however, organic compounds are defined as those compounds which have carbon-hydrogen bonds, and inorganic compounds, those without. Thus carbonic acid is inorganic, whereas formic acid, the first fatty acid, is organic, although it could as well be called "carbonous acid".
This definition would leave out non-hydrogen-containing fluorocarbons like Teflon and Freon, or put them in a grey area, since they are carbon-containing and have many of the same properties of C-H compounds, due to the similarity of the C-F bond to the C-H bond.
Most pure organic compounds are artificially produced; however, the term "organic" is also used to describe products produced without artificial chemicals (see organic production).
