IUPAC<unk>  is a system of naming chemical compounds and of describing the science of<unk>  in general. It is developed and kept up to date under the auspices of the<unk><unk>  of<unk>  and<unk><unk>  (IUPAC).
The rules for naming organic and inorganic compounds are contained in two publications, known as the Blue Book and the Red Book respectively. A third publication, known as the Green Book, describes the recommendations for the use of symbols for physical quantities (in association with the IUPAP), while a fourth, the Gold Book, contains the definitions of a large number of technical terms used in<unk> . Similar compendia exist for biochemistry (in association with the IUBMB), analytical<unk>  and macromolecular<unk>  . These books are supplemented by shorter recommendations for specific circumstances which are published from time to time in the journal<unk>  and<unk><unk> .
This article treats the system of<unk>  in general, notably its aims and historical development. Separate articles treat the naming of organic compounds and inorganic compounds in more detail.
International Union of Pure and Applied Chemistry nomenclature
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Allergy classification
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Clinical ecology