To verify the dynamic stability of the novel carbon allotropes, their phonon properties were studied. The phonon band structures obtained from a high resolution of the tetragonal Brillouin zone according to Togo et al. are shown in Fig. . The bands (red lines) develop along the main directions of the tetragonal Brillouin zone (horizontal x-axis), separated by vertical lines for better visualization, while the vertical direction (y-axis) shows the frequencies ω, given in terahertz (THz).