The remaining bands correspond to optic modes. In 'glitter' C 6 and B 2 C 2 N 2 (Figs. and) the highest bands are at 50 THz, i.e. the magnitude is higher than that in diamond (ω  40 THz according to Raman vibration spectroscopy ). Such high frequency is assigned respectively to the C2-C2 and C-N stretching. Thus, both phases are anisotropic as it already follows from their crystal structures.