Phosphonitrilic Chlorides from Phosphorus Pentachloride

Under suitable conditions, PCL 5 reacts and quantitatively with NH 4 Cl to form [Cl 3 P = N–PCl 3 ] [PCl 6 ], which, with additional PCl 5 and NH 4 Cl, is transformed to [Cl 3 P = N–PCl 2 = N–PCl 3 ] [PCl 6 ].The cation of the latter compound and the NH   4 +ion react with ring closure to form [NPCl 2 ] 3 , together with longer chains which can yield with NH   4 +either [NPCl 2 ] 4 or, for example, Cl 3 P = N‐(PCl 2 = N) n ‐PCl 2 = NH. The salt‐like intermediates of the phosphonitrilic chloride synthesis react with S0 2 to form the oxygen‐containing products, Cl 3 P = N–P(O)Cl 2 and Cl 3 P = N–PCl 2 = N–P(O)Cl 2 . Sulfur analogs are also easily obtained. The constitution of the compounds was determined by nuclear magnetic reasonance spectroscopy.