Nomenclature, heteropoly compounds

Current knowledge of the structure and properties of heteropoly compounds necessitates a more adequate nomenclature of such compounds by taking into consideration both the structure and degree of polymerization and oxidation of the central atom. 

The nomenclature rules to be presented follow in the main the 1957 report of the Committee on Inorganic Nomenclature of the International Union of Pure and Applied Chemistry. The discussion here will be brief, and the methods of nomenclature of heteropoly acids, intermetallic compounds, unusual oxygen acids, isotopically enriched compounds, and silane derivatives will not be described. 

These types are not all sharply divided, but many compounds may be considered to belong to two or more of these classifications. Although schemes of nomenclature are available for all of these types, the schemes are reasonably satisfactory for only three (solvates, double salts, and iso- and heteropoly acids and salts). This situation is the more regrettable because so large a proportion of the total number of known compounds belongs to the class of higher order compounds and modem research is rapidly enlarging both the number and complexity. 

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