Domain-averaged Fermi holes - a new means of visualization of chemical bonds. Bonding in hypervalent molecules

Abstract

The nature of bonding in several hypervalent molecules was analyzed at the ab initio SCF level using the recently proposed methodology based on the analysis of domain-averaged Fermi holes. The results of the analysis demonstrate that, for suciently¯exible basis sets, the expansion of the valence shell does indeed take place for second row central atoms in PF 5 , SF 4 , and SF 6 . On the other hand, no such expansion was observed for the ®rst row N atom in NF 5 .

Structure and bonding in binuclear metal carbonyls from the analysis of domain averaged Fermi holes. I. Fe2(CO)9and Co2(CO)8

“…In such cases therefore the approximate form of the analysis can represent a real alternative and we believe that its use in our case is able to provide realistic and reliable insight into the structure of the studied carbonyl complexes similarly as in previous studies of other transition metal complexes. [40][41][42] Such a belief is corroborated by the experience with comparing both approaches on smaller systems, 38,39,45 which clearly suggest that the picture of bonding emerging from the ''exact'' and approximate DAFH analysis is generally very similar and especially at the level of the qualitative description, that is the aim of our study, no important differences are observed.…”

Chemical structures from the analysis of domain‐averaged fermi holes. Nature of the MnMn bond in bis(pentacarbonylmanganese)

“…Because the details of the new methodology are sufficiently described in the original studies, [15][16][17][18][19][20][21] we consider it sufficient to remenber here only the basic principles of the approach to the extent necessary for the purpose of this study. The domain-averaged Fermi holes are defined by eq.…”

“…[7][8][9][10][11][12][13][14] Nontrivial and controversial bonding patterns have also been dealt with in our recent studies based on the analysis of the so-called domain-averaged Fermi holes. [15][16][17][18][19] In view of the success of this new theoretical methodology in the description and visualization of the complicated bonding patterns, we decided to also apply it to the scrutiny of another widely discussed metalmetal bond whose nature is still not completely understood, namely the Mn-Mn bond in the bis(pentacarbonylmanganese). 20 -26 Most of the studies of the bonding in this carbonyl cluster are based on the topological analysis 27 of either experimental 22,23,26 or calculated 23 electron density, but despite considerable effort the nature of this bond is still far from being clear.…”

Electron pairing and chemical bonds: Pair localization in ELF domains from the analysis of domain averaged Fermi holes

“…[29][30][31][32][33][34] The domain-averaged Fermi holes can most straightforwardly be introduced by eq. (1) in which (r 1 ,r 2 ) and (r 1 ) are the pair and first order density, respectively, and the averaging (integration) is performed over the finite domain O.…”