Tetrametaphosphimates crystal structures

Although tri- and tetrametaphosphimates have been studied extensively, only a few single-crystal structure analyses had been conducted until recently. Tables III and IV, respectively, give a summary of the crystallographic data of all hitherto known structures. 

The crystal structure determinations of tetrametaphosphimates showed that N-H 0 hydrogen bonds between the ring anions play an important structure directing role. The iPCfNH) rings adopt approximately a chair, boat, or saddle conformation. Examples for conformations in (P02NH)t ions as well as some structural aspects of tetrametaphosphimates are given in Fig. 3. 

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