Pyrophosphoryl halides

Some more complex oxohalides are known, of which the pyrophosphoryl halides, X2P(0)—O—P(0)X2, X = Cl, F are best known. 

Direct oxidation of chloridites (6.320), the action of chlorine or sulphuryl chloride on trialkyl phosphites (6.349) or on dialkyl phosphonales (5.335) can be employed. A method of historical interest is to heat a silver phosphorofluoridate with an alkyl halide (5.336). A halophosphate is also obtained by reacting a pyrophosphoryl halide with ethanol at low temperature (5.337). 

Pyrophosphoryl chloride is hydrolysed by water and it reacts readily with ammonia to give the tetramide (H2N)2P(0)0P(0)(NH2)2 and other products (Chapter 7). Polymeric (POjCOn can be prepared by the oxidation of PCI, with NjO. The mixed halide FC1P(0)0P(0)C1F can be obtained from POCljFandPAo. 

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