Theoretical studies of inorganic compounds.: Part XXVIII.: Energy decomposition analysis of the chemical bond in main group and transition metal compounds

The nature of the chemical bond in the main group diborane(4) compounds X2B-BX2 (X = H, F, Cl, Br, I) and in the Fischer- and Schrock-type transition metal carbene and carbyne complexes and heavier homologues (CO)(5)W-CH2, (CO)(5)W-E(OH)(2), Cl4W-EH2, Cl(CO)(4)W-EH and Cl3W-EH (E = C, Si, Ge, Sn, Pb) have been investigated with an energy decomposition analysis (EDA). The results give a deep insight into the nature of the chemical interactions. The EDA results can be used as a bridge between the heuristic models of experimental chemists which have been proven as useful ordering schemes for experimental observations and the physical mechanism which leads to a chemical bond. At the time the data give a well defined qantitative answer to the questions about the strength of the covalent and electrostatic interactions and about the contributions of sigma and pi electrons to the covalent bond.