The NMR data for the above compounds include information on meta phosphonyl compounds and diylides, and are given in Table F which follows. The relatively small numbers of compounds in this class make it difficult to find a general relationship between 31P chemical shift and structure. There is wide variation of substituents of phosphorus and a corresponding large range of 31P chemical shifts. The 31P chemical shifts vary from 13 to 297 ppm and are generally downfield of those of the corresponding λ5, σ4 compounds.