Abstract
The results of a systematic study of spiro -cyclotri/tetraphosphazenes with ferrocenyl pendant arm on the basis of correlation between structural parameters were presented. The main parameters were obtained from Xray crystallography and (31)P NMR results in order to investigate the relationship between the δ P (spiro ) shift values and endocyclic and exocyclic NPN bond angles, and electron density transfer parameters. Structural parameters derived from 11 types of the ferrocenyl cyclophosphazene derivatives with 5- to 7-membered spiro -rings introduced to the literature from our research group were studied and compared with each other.