It is relevant to observe interconnectedness between solid state and organic domains regarding the chemistry of carbon. Inspired from 2D 1,4-cyclohexadiene planar molecule (Fig. ) was enclosed in the so called 'glitter' structure with tetragonal hexacarbon C 6 , thus mirroring the molecule in a crystal . The structure shown in Fig. consists of corner-sharing tetrahedra of C(sp 3 ) -white spheres-in the a,b plane, connected by C=C double bonds along c-direction. The crystal data detailed in Table point to a distorted tetrahedron with angles departing from the perfect tetrahedron angle C-C-C = 109.47° found, for instance, in methane CH 4 or diamond. Due to the two kinds of connectivity (Fig. polyhedral view), the calculated mechanical properties identified tet-C 6 as ultra-hard with the particularity of being metallic -whence the 'glitter' designation-while being characterized with less cohesive energy and hardness than diamond . A major role in the high hardness of diamond is played by the corner sharing C4 tetrahedra and the C(sp 3 ) hybridization characterizing the structure (Fig. ). Considering the tetrahedron as elementary building unit, and using above tetragonal C 6 , an isolated tetrahedron 'in a box' can be identified from halving the structure (see red line crossing in Fig. ), letting obtain a tetrahedron within C 3 stoichiometry. The structure shown in Fig. obtained after geometry optimization onto the ground state with quantum mechanical calculations based on the density functional theory DFT is described in the tetragonal system (cf. Table ). However, such tetrahedron was found less cohesive, explained by the lack of 3D periodicity. Additional carbon at 0,0,0 (corner positions, Fig. ) let gain 3D periodicity with corner-sharing tetrahedra in all directions. The resulting tet-C 4 was found as cohesive as diamond and equally characterized with unique interatomic distance and angle as shown in Table .