Compositional nomenclature binary compounds

When atomic theory developed to the point where it was possible to write specific formulae for the various oxides and other binary compounds, names reflecting composition more or less accurately then became common no names reflecting the composition of the oxosalts were ever adopted, however. As the number of inorganic compounds rapidly grew, the essential pattern of nomenclature was little altered until near the end of the 19th century. As a need arose, a name was proposed and nomenclature grew by accretion rather than by systematization. 

Compositional names are either of the stoichiometric type (which, furthermore, are of the binary type except in the case of homoatomic species) or of the addition compound type. Compositional nomenclature is used if little or no structural information is to be conveyed... 

During Werner s time compositional nomenclature for binary compounds had already been agreed upon in much the same way as today, and names such as manganese dichloride and manganese monooxide were in common use to express information about stoichiometric compositions only. For complex compounds, this type of nomenclature had simply b n extended as in the notational example 3 KCN,Fe(CN)3. Werner realized that diis notation could be modified to became a nomenclature including structural information, when this was available, and potassium hexacyanoferriate is his ingenious proposal (2). This is an example of what is today referred to as additive nomenclature or coordination nomenclature, as opposed to the substitutional nomenclature of organic chemistry. 

Additive nomenclature1 is based on the combination of element names or roots of element names and/or ligand names. The simplest and oldest additive nomenclature is binary nomenclature that expresses two components, e.g. sodium chloride. The cationic or electropositive portion of the compound expressed in a binary name is the element name unchanged or a group name ending in -ium , and the anionic or electronegative portion of a compound expressed in the name ends in -ide, -ite or -ate. The proportions of cations and anions in neutral compounds are indicated by Stock numbers or simple or multiplicative prefixes (see Section 3.3.2). Additive nomenclature denotes composition. For examples see Table 1. 

The nomenclature pattern established in binary nomenclature is also used to indicate the composition of more complex entities, including ionic coordination compounds. Electropositive constituents are cited in alphabetical order before the electronegative constituents, which are also cited in alphabetical order. For examples see Table 2. 

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