The bonding in and stability of dimeric group 15-compounds of the general formula E2R2 has been investigated in the past mainly with E = N, P and R = H, CH3. In this study, the authors extend these investigations to all group 15-elements E with E = N, P, As, Sb, Bi and analyze the character of the E-E bond for E2H2 compounds with the aid of Atoms in Molecule (AIM) and natural bond orbital (NBO). the authors carried out a comprehensive-theoretical investigation of covalent E2H2 compounds and the changes in bonding electron density upon mono- and diauration. The theoretical results clearly show that the N-N bond in N2H2 gets longer upon complexation with AuCI while the P-P-, As-As-, Sb-Sb- and Bi-Bi-bonds exhibit the opposite trend, although the E-E Wiberg bond indices (WBI) decrease upon auration. The condition of a negative total energy (H(r) 0) in the bonding region holds for all E-E bonds of molecules in the AIM analysis. All complexes E2H2, E2H2AuCI, E2H2(AuClh complexes (E