An Update on Multiple Bonding between Heavier Main Group Elements: The Importance of Pauli Repulsion, Charge-Shift Character, and London Dispersion Force Effects
Philip P. Power
Abstract
An update on some recent developments in the bonding of compounds with multiple bonds between heavier main group elements is the major theme of this review. A brief historical summary of the field is given in the Introduction. This is followed by a discussion of the major factors affecting the multiple bonding between these elements and the approaches used in the interpretation of that bonding. This organizational format follows that used in two earlier comprehensive reviews covering the area. However, this review is not a comprehensive one and it concerns compounds with homonuclear multiple bonds only. It emphasizes two new themes which involve London dispersion force (LDF) energies and charge-shift (CS) effects that were not treated in the earlier reviews. Although LDF effects are always present in molecular species, it is now clear they can be of decisive importance in the stability of the multiple-bonded compounds, especially those where the multiple bond is weak.