σ-hole bonding between like atoms; a fallacy of atomic charges
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- Politzer, P., Murray, J.S. & Concha, M.C. J Mol Model (2008) 14: 659. doi:10.1007/s00894-008-0280-5
Covalently bonded atoms, at least in Groups V–VII, may have regions of both positive and negative electrostatic potentials on their surfaces. The positive regions tend to be along the extensions of the bonds to these atoms; the origin of this can be explained in terms of the σ-hole concept. It is thus possible for such an atom in one molecule to interact electrostatically with its counterpart in a second, identical molecule, forming a highly directional noncovalent bond. Several examples are presented and discussed. Such “like-like” interactions could not be understood in terms of atomic charges assigned by any of the usual procedures, which view a bonded atom as being entirely positive or negative.