Sigma holes are described as electron-deficient regions on atoms, particularly along the extension of covalent bonds, due to non-uniform electron density distribution on the surface of these atoms. A computational study of MXnY4-n molecules (n = 1-4; M = C, Si, Ge; X, Y = F, Cl, Br) was undertaken and it is shown that the relative sigma hole potentials on M due to X-M and Y-M can be adequately explained in terms of the variation in the valence electron population of the central M atom. A model is proposed for the depletion of the M valence electron population which explains the trends in sigma hole strengths, especially those that cannot be accounted for solely on the basis of relative electronegativities.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry