Nomenclature of oxoacids, 66

Historically, where the central element forms oxoacids in two oxidation numbers, the higher state is indicated by the suffix -ic (as in phosphoric acid, H3PO4, phosphorus oxidation number +5), and the lower state by the suffix -ous (as in phosphorous acid, H3PO3, phosphorus oxidation number +3.) 

If more than two oxidation numbers are involved, the prefixes per- and hypo- are used as well per- denotes the highest oxidation number, and hypo- the lowest oxidation number. Thus, the oxoacids of chlorine are shown in Table 11.5. 

Oxoanions derived from -ic acids are given the ending -ate-, examples are provided by the sulfate ion, S04 , the phosphate ion, P04 , the chlorate ion, C103 , and the perchlorate ion, C104.  

Oxoanions derived from -ous acids are given the ending -ite-, examples are the sulfite ion, S03 , the nitrite ion, N02, the hypochlorite ion, OCl , and the phosphite ion, P03 . 

Condensed forms of oxoacids are also distinguished by means of prefixes. Thus, the prefix ortho- refers to the monomeric , or most highly hydroxylated, form, and the prefix meta- refers to the polymeric , or least highly hydroxylated, form. 

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