Spiers Memorial Lecture - Quantum chemistry: The first seventy years; Anatomy of bond formation. Bond length dependence of the extent of electron sharing in chemical bonds from the analysis of domain-averaged Fermi holes; Bonding indicators from electron pair density functionals; Source function description of metal-metal bonding in d-block organometallic compounds; Forces in molecules; On the definition of local spin in relativistic and nonrelativistic quantum chemistry; General Discussion; Calculation of negative electron affinity and aqueous anion hardness using Kohn-Sham HOMO and LUMO energies; The physical basis of the hard/soft acid/base principle; Use of DFT-based reactivity descriptors for rationalizing radical addition reactions: applicability and difficulties; Carboranes: chemical concepts derived from the AIM study of the experimental and theoretical electron density distribution functions; On the accurate estimation of intermolecular interactions and charge transfer: the case of TTF-CA; General Discussion; The physical origin of large covalent-ionic resonance energies in some two-electron bonds; Quantifying resonance through a Lewis Valence Bond approach: application to haloallyl and carbonyl cations; The unusual electronic mechanism of the [1,5] hydrogen shift in (Z)-1,3-pentadiene predicted by modern valence bond theory; On the interpretation of valence bond wavefunctions; Current-density maps as probes of aromaticity: Global and Clar ring currents in totally resonant polycyclic aromatic hydrocarbons; Electron sharing indexes at the correlated level. Application to aromaticity calculations; Critical analysis of the local aromaticity concept in polyaromatic hydrocarbons; General Discussion; Direct estimate of conjugation and aromaticity in cyclic compounds with the EDA method; Charge transfer, chemical potentials, and the nature of functional groups: answers from quantum chemical topology; Energy partitioning schemes: a dilemma; Highly polar bonds and the meaning of covalency and ionicity-structure and bonding of alkali metal hydride oligomers; The dithiolene ligand-innocent or non-innocent? A theoretical and experimental study of some cobalt-dithiolene complexes; General Discussion; Concluding remarks
