Phosphorus pseudohalides

The PN bond length is practically the same (1.68 A) in all the phosphorus pseudohalides studied. It hardly differs from the PN bond length in halogeno-substituted... 

However, the PN bonds in phosphazenes are considerably shorter than those observed in both amino derivatives and phosphorus pseudohalides, presumably because there is no actual alternating of single and double bonds in the formally unsaturated (NPX2) ring systems. These bonds are characterized by marked sensitivity to the influence of the substituents at the phosphorus atom ... 

Paralleling the various phosphorus trihalides are numerous pseudohalides and mixed pseudohalide-halides of which the various isocyanates and isothiocyanates are perhaps the best known. Most are volatile liquids, e.g. 

Depending on the substituents, a variety of reaction types have been observed in the reaction of HFA and pseudohalides of phosphorus(III). Most... 

This method may be used for the preparation of other perfluorinated alkanesulphonyl-, arenesulphonyl-, and alkanecarbonyl-amides. Several reactions of the pseudohalide were studied, but perhaps the most interesting are the reaction under pressure at 160 °C with phosphorus pentasulphide to give the previously unknown compound CF3SOzNCS, and the reaction with phosphorus pentachloride under the same conditions to give CF3S02NCC12. 

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