To induce trigonal 3D carbon  tetrahedral 3D carbon G2D-like change, extra carbons were inserted (white spheres) at 4a (0,0,0) position followed by a geometry relaxation to the ground state. Figure showing the fully relaxed structure projected onto x0z exhibits the characteristics of a 'tilted' configuration with an angle of 26° alike the lig trigonal initial matrix, featured on the RHS of Fig. . The 3D projection in Fig. is characterized by C4 tetrahedra building the structure, alike diamond. In fact, submitted to TopCryst program, the dia 4/6/c1; sqc6 topology was found for novel C 20 . The crystal data of the new structure are given in Table , and the crystal parameters of diamond are also given for comparison. The chracateristic paratemeters of C 20 show indeed similar magnitudes as diamond for the interatomic distance, the atom-averaged volume, the density as well as the total energy per atom and the cohesive provided in the last column of Table . Lastly, further crystal symmetry analysis was carried out by submitting the resulting crystal structure CIF file to "PLATON" crystal analyzer (). Such analysis did not lead to any proposition of alternative space group that could be related to diamond. Then, we propose the label of "pseudo-diamond" to novel C 20 .