Blaser and Worms Nomenclature

About 60 years ago, condensed oxo-acids, additional to those cited above, were discovered and characterised. This quickly led to the realisation that an almost infinite number of such compounds were possible, at least in principle. These compounds are substituted condensed phosphates in which some of the P-0 and P-O-P linkages are replaced by P-H and P-P linkages. 

The Blaser and Worms nomenclature for oxo-adds is based on the fact that all the anions can be considered as built from units of the type (5.246), where X and Y are any of the elements O, P or H. 

These structural units are assigned formal oxidation numbers as given in Chapter 3.1. Thus, orthophosphoric, phosphorous and hypophosphorous acids may be termed 5/P, 3/P and 1/P acids, respectively. Pyrophosphoric acid is 5/P-0-5/P and hypophosphoric acid is 4/P-4/P. Isomers can be clearly distinguished on this system. The two acids with the formula H4P2O5, for example, are written as 3/P-0-3/P and 2/P-4/P. 

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