Oxyacids and Related Compounds

Emeleus, H.J., Haszeldine, R.N., and Paul, R.C., Organometallic and organometaUoidal fluorine compounds. Part 12. Bistrifluoromethylphosphinic acid and related phosphorus oxyacids, J. Chem. Soc, 563, 1955. 

Compounds with phosphorus as the key element that have been investigated for extreme-pressure additive activity add up to an impressively long list. But only a few of them have turned out to be of practical utility and these are predominantly esters of phosphoric acid or derivatives of thiophosphoric acid. In this section we shall be concerned only with those compounds in which phosphorus in combination with oxygen constitutes the key structure dithiophosphates and related derivatives are discussed in Section 11.2.6. The four main types of phosphorus oxyacid esters treated in the present section are shown in Table 11-12. Phosphoric and phosphorous acids are trifunctional hence there are three or-ganophosphorus structures to be considered the neutral triester, the monoacidic diester and the diacidic monoester. 

Tellurium forms inorganic compounds very similar to those of sulfur and selenium. The most important teUurium compounds are the teUurides, haUdes, oxides, and oxyacids (5). Techniques and methods of preparation are given in the Uterature (51,52). The chemical relations of teUurium compounds are iUustrated in Figure 2 (53). 

A comprehensive and detailed review of the literature relating to the decomposition reactions of the salts of halogen oxyacids has recently been given by Solymosi [1279], This book discusses many aspects of the chemical characteristics of this group of compounds. It includes a large amount of kinetic data and provides access to the original publications. 

Quite often, we find nonsystematic nomenclature used in the literature dealing with organophosphorus compounds. This results in unnecessary confusion, as systematic nomenclature is easy to use and understand. Nomenclature based on the oxidation state of the phosphorus center eliminates the confusion and helps to promote understanding of the chemistry as well as to facilitate communication. Table 1.1 shows structures for tricoordinate and tetracoordinate phosphorus compounds related to oxyacids with their English general names. Also noted are the names for simple esters of the parent acids. They are organized based on oxidation state and the number of bonds of the carbon-phosphorus type. 

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