THE FORCE-FIELD OF THE TRIAZINIC RING C3N3

We have obtained a set of force constants for the symmetric triazinic ring C3N3, from data on the vibrational frequencies of the s-triazine, trifluoro-s-triazine and trichloro-s-triazine molecules. The procedur e consists on several steps of refinement, concluding with the determi nation of the force constants of the non-common part of each individua l species. The force field of the common block has been used to calcul ate the vibrational spectrum of tribromo-s-triazine, leading to satisf actory results.