Common, non-systematic names

Systematic nomenclature was introduced at a relatively late stage in the history of chemistry, and thus common names had already been coined for a wide range of chemicals. Because these names were in everyday usage, and familiar to most chemists, a number have been adopted by lUPAC as the approved name, even though they are not systematic. These are thus names that chemists still use, that are used for labelling reagent bottles, and are those under which the chemical is purchased. Some of these are given in Table 1.4, and it may come as a shock to realize that the systematic names school chemistry courses have provided will probably have to be relearned . 

The use of the old terminology n- (normal) for unbranched hydrocarbon chains, with i- (iso), s-(secondary), t- (tertiary) for branched chains is still quite common with small molecules, and can be acceptable in lUPAC names. 

Structure Systematic name lUPAC approved name 

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Gunstone, F. D., and Adlof, R. O., Common (non-systematic) Names for Fatty Acids, www.aocs.org/member/division/analytic/fanames. asp, 2003. 

An abbreviation for an organic ligand should be derived from a name consistent with the current rules for the systematic nomenclature of organic compounds.4 (For some ligands a non-systematic name is included in Table VII if it was the source of the abbreviation and if that abbreviation is still commonly used.) New abbreviations should further be constructed according to the following recommendations ... 

The traditional, non-systematic names. Many of these linger on, especially for simpler or more common molecules. 

Each vegetable oil is characterised by its fatty acid composition which nevertheless may vary somewhat depending upon factors such as weather, soil conditions and variety. Typical fatty acid compositions of the most common vegetable oils, which together account for over 90% of world production, are given in Table 6.1 In the table, both non-systematic names and numerical notation are given, as an example, 18 2 refers to a fatty acid with 18 carbons and two double bonds. 

Much of the early work on amphiphiles was undertaken on soaps and lipids based on fatty acids, and the corresponding non-systematic chemical names of these parent compounds and their derivatives are still commonly encountered. For convenience, Table 4.1 lists the systematic and trivial names of fatty acids, along with their structures. The names of derivatives are based on these for example sodium dodecyl sulphate is (still ) sometimes referred to as sodium lauryl sulphate. Other non-systematic names also exist to cause further confusion For example, hexadecyl (Cie chain) compounds are often termed cetyl derivatives. The use of the term fatty here and elsewhere is used to indicate an alkyl chain with 12 or more carbon atoms, i.e. a hydrocarbon that forms fats. 

Certain inorganic and simple carbon-containing compounds are commonly given non-systematic or semi-systematic names containing the word acid . Examples are boric acid or orthoboric acid, metaboric acid, phosphoric acid, diphosphoric acid, cyc/o-triphosphoric acid, cafena-triphosphoric acid, dithionous acid, peroxodisulfuric acid or peroxydisulfuric acid, etc. These names are unique in modern nomenclature in that, interpreted literally, they describe a particular chemical property of the compounds in question. Systematic names are otherwise based solely on composition and structure. 

Where common names are used for organic compounds, the systematic name is given as well at the first mention. Common names are widely used in the chemical literature, in industry and commerce, and there is a great divergence in the use of systematic as opposed to non-systematic nomenclature in the English-speaking world. 

Synonym A synonym in common use. When the primary name is non-systematic, a systematic name may appear here. 

Monosubstituted benzene derivatives are usually named after benzene (CgHg), although some non-systematic or common names (in brackets) are still used. 

Trivial names (or common names) are non-systematic historical names, which are the most frequent naming system used in literature. Most Palmitoleic acid common fatty acids have trivial names in addition to their systematic names (see below). These names frequently do not follow any pattern, but they are concise and often unambiguous. 

Binary covalent compounds are typically formed by the combination of two non-metals. Some are so familiar that we use their common names, such as ammonia (NHj), methane (CH/, and water (H2O), but most are named systematically ... 

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