Name construction substitutive nomenclature

When it is required to convey more information than is implied by a simple compositional name, other approaches to name construction are adopted. The structure of the compound under consideration generally dictates the name adopted, even though a compound may be named correctly in more ways than one. For molecular compounds, substitutive nomenclature, originally developed for naming organic compounds and the oldest systematic nomenclature still in use, is generally used. 

Generally, nomenclature systems use a base on which the name is constructed. This base can be derived from a parent compound name such as sil (from silane) in substitutive nomenclature (mainly used for organic compounds) or titan a central atom name such as cobalt in additive nomenclature (mainly used in coordination chemistry). 

Generally, nomenclature systems require a root on which to construct the name. This root can be an element name (e.g. cobalt or silicon ) for use in additive nomenclature, or can be derived from an element name (e.g. sil from silicon , plumb from plumbum for lead) and elaborated to yield a parent hydride name (e.g. silane or plumbane ) for use in substitutive nomenclature. 

Constructing a substitutive name generally involves the replacement of hydrogen atoms in a parent structure with other atoms or atom groups. Related operations, often considered to be part of substitutive nomenclature, are skeletal replacement (Section IR-6.2.4.1) and functional replacement in oxoacid parents (Section IR-8.6). Note that some operations in parent hydride-based nomenclature are not substitutive operations (e.g. formation of cations and anions by addition of H+ and H, respectively, cf. Sections IR-6.4.1 and IR-6.4.5). Names formed by the modifications of parent hydride names described in those sections are still considered part of substitutive nomenclature. 

The above exposition is only a very brief overview of the most important principles of substitutive nomenclature. In Ref. 1, an extensive system of rules is developed for choosing one name among the many unambiguous substitutive names that may often be constructed for organic compounds. A corresponding extensive set of rules has not been developed for non-carbon-containing compounds, partly because many such compounds can just as well be given additive names (Chapter IR-7), and often are. 

The trivial name acetic acid is the most commonly used and preferred lUPAC name. The systematic name ethanoic acid may be used as a valid lUPAC name. The name acetic acid derives from acetum, the Latin word for vinegar, and is related to the word acid itself The synonym ethanoic acid is constructed according to the substitutive nomenclature of the lUPAC. 

The structural repeating unit is named by citation of one or more multivalent radicals of regular substitutive nomenclature. The selection of the preferred SRU, its orientation, and the construction of the name, proceeding from left to right, follows the same rules as those in the lUPAC recommendations for the CRU. In CA names, however, die names of die radicals are fidly systematic, as explained and contrasted above. The empirical formula is enclosed m parendieses followed by a subscript... 

A few examples of other functional nomenclature are also included in Table IR-8.2 e.g. phosphoryl chloride, sulfuric diamide). These particular names are well entrenched and can still be used, but this type of nomenclature is not recommended for compounds other than those shown. Again, additive and substitutive names may always be constructed, as exemplified in the Table. 

Inorganic compounds produced synthetically should be called by their chemical name based on current Intemational Union of Pure and AppHed Chemistty ( lUPAC ) conventions, under the so-called Red Book (lUPAC Nomenclature of Inorganic Chemistry. Recommendations 1990, G.J. Leigh (ed.) Blackwell Scientific PubHcations, Oxford, 1990). In practice lUPAC rules offer a range of possible constructions and therefore certain practices were adopted within these rules. For example, forms such as aluminate or stannate have not been used, these being substituted by constructions such as xxx aluminium oxide and xxx tin oxide the compounds concerned are then classed as oxides of the first-named element However, as the list currently stands it is not wholly consistent for example, chromate has been used. 

Since the lUPAC nomenclature system relies totally on the pivotal concept of the parent structure to which, in a second sphere, substituents are assigned, it appeared advisable to maintain this division also for the chapters of this book. Thus, we begin with the exposition of the nomenclature rules for parent structures and, in the second chapter, proceed with the discussion of the different types of nomenclature for substituted systems, radicals, and ions in the third chapter specific classes of functional compounds are addressed, followed, in the forth chapter, by the treatment of metal organyls and, in the fifth, of carbohydrates. The concluding sixth chapter takes up once again the construction of the final names of complex compounds including isotopic modifiers and stereochemical descriptors. 

---