Characterisation of phosphazenes and their polymers

Phosphazenes are compounds with the general formula (NPX2)n where X = F, Cl, Br, organic (e.g. alkyl, aryl, alkoxide, aryloxide, amine, mercapto) and n = 3, 4, The lower members, n = 3, 4, 5 are cyclic, while the higher members are linear polymers. Perhaps surprisingly, for n = 3 and X = F and Cl, there are only incomplete assignments of the vibrational spectra. This arises because in the gas phase, the molecules are planar D3h species and this is largely retained in the solid state. This means that there are modes that are forbidden in both the infrared and Raman spectra. Since all modes are allowed in the INS spectrum, this is the only technique that provides access to these modes. It is proposed to simultaneously measure the INS and Raman spectra of hexa- and octafluorocyclotriphosphazene, polydifluorophosphazene, hexa- and octachlorocyclotriphosphazene and polydichlorophosphazene