When assigning the IR spectrum of hexachlorocyclotriphosphazene there are two prominent peaks (one due to the nitrogen-phosphorus bond and the other due to the phosphorus-chlorine bond).
There is one peak at 1179cm⁻¹ and another at 594cm⁻¹. I think that the peak at 1179cm⁻¹ is due to the phosphorus-nitrogen bond and the peak at 594cm⁻¹ is the phosphorus-chlorine bond.
My reasoning for this is that the phosphorus-nitrogen bond is shorter and therefore stronger thus it will have the higher stretching frequency.
Is my reasoning correct?