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Number crunching Browsing a large number of structures, people have tried to gain an understanding of common properties. The statistical analysis of chemical structures is called chemical informatics. The Beilstein database contains a large collection of organic compounds. A cheminformatics study involving 5.9 million substances and 6.5 million reactions showed that the organic compound universe consists of a core of around 200,000 molecules strongly connected to each other and a large periphery (3.6 million molecules) around it . 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: 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 by definition of its known occurrence only in the urine of living organisms, from potassium cyanate and ammonium sulfate by Friedrich Wöhler in the Wöhler synthesis. The dividing line between organic and inorganic is presently contested, and is historically arbitrary. Generally speaking, organic compounds are often defined as those compounds which have carbon-hydrogen bonds, and inorganic compounds, those without. This even-more specific definition has some problems, notably that (with some historical irony) it excludes urea itself as an organic, since urea has carbon and hydrogen, but no carbon-hydrogen bond. In this scheme, carbonic acid is inorganic and so is oxalic acid, whereas formic acid is organic. This definition would also 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 today are artificially produced, although a few are extracted from natural sources because they would be far too expensive to produce artificially (for example, sucrose). See also | ||||||||||
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