The Relevance of the ELF Topological Approach to the Lewis, Kossel, and Langmuir Bond Model

Abstract

The electron localization function (ELF) approach to chemical bonding is revisited as a tool to check the falsifiability of the Lewis hypotheses. It is shown that the boundaries of the ELF basins correspond to zero-flux surfaces of the local integrated same spin pair probability enabling the determination of regions of the molecular space which maximizes the opposite spin pair density and therefore groups of electrons. The ELF yields a partition into core and valence basins which matches the Lewis model. The valence basins which correspond either to electron lone pairs or to bonds enable the definition of atomic valence shells in which bonding basins are shared by at least two atomic valence shells. The ELF basin populations take into account the mesomery which explains the deviations from ideal values. The organization of the basins around the atomic cores often complies with the VSEPR rules. The behavior of the ELF basins upon deformation of the nuclear frame sheds light onto the reactivity and reaction mechanisms, whereas the basin compressibilities provide chemical explanations of pressureinduced phase transitions.

Curly arrows meet electron density transfers in chemical reaction mechanisms: from electron localization function (ELF) analysis to valence-shell electron-pair repulsion (VSEPR) inspired interpretation

“…104 This function can be approximated by the kernel of the electron localization function (ELF) of Becke ans Edgecombe. 105 This statement is supported by calculations on atoms 103,106 which show that the shell boundaries calculated by ELF and by the minimization of the variance of the shell populations almost coincide. In molecules, small variations of the basins bounding surfaces off their ELF position increases the variance of the population.…”

What is the hydrophobic interaction contribution to the stabilization of micro-hydrated complexes of trimethylamine oxide (TMAO)? A joint DFT-D, QTAIM, and MESP study

“…Protonated basins can be localized and characterized, as well as electron pairs in keeping with the Lewis structures. 17,18 Furthermore, after geometry optimization, all the hydrated complexes were further studied by means of the QTAIM 19 approach in order to analyze both qualitatively and quantitatively the intermolecular interactions involved in the complexes.…”

Topological analysis of the metal-metal bond: A tutorial review

“…This ELF picture of the M-M bond may be related to charge-shift bonding, introduced recently for the description of the C-C bonds of the propellane ring and for hydrogen-halide bonding [292]. Charge-shift or M-M bonds are at the borderline of electron-shared and closed-shell interactions because their disynaptic basin may be absent or replaced by a protocovalent pair of monosynaptic basins [40]. From this topological picture, the Mo-Mo multiple bond may be described by a resonance between several electron configurations due to the fluctuation of the metal d electrons within the cores.…”

“…Generally σ-bonding plays by far the dominant role, while π and δ components are of lesser importance [36]. Similarly to charge-shift bonds, such M-M bonds are indeed at the borderline of the electron-shared and electron-unshared interactions [40].…”