The second part of Table shows cohesive chemical systems all larger than the preliminary results at upper part of the table. C 6 which contains both tetrahedral and trigonal carbon types is less cohesive than diamond made of purely C(sp 3 ) with E coh. /at.= -2.49 eV/at. (cf. ). Si 2 C 2 N 2 is confirmed to be cohesive with E coh. /at. magnitude smaller but close to that of Si 2 C 4 . Crystallographically, the replacement of C1 by Si in C1 2 C2 4 ("glitter" C 6 , Fig. ) leads to hypothetic silicon dicarbide Si 2 C 4 (Fig. ) which shows the same tetrahedral stacking as in C 6 .