Statistical Analysis of $sigma$-Holes: A Novel Complementary View on Halogen Bonding

To contribute to the understanding of noncovalent binding of halogenated molecules with a biological activity, electrostatic potential (ESP) maps of more than 2,500 compounds were thoroughly analysed. A peculiar region of positive ESP, called $sigma$-hole, is a concept of central importance for halogen bonding. We aim at simplifying the view on $sigma$-holes and provide general trends in organic drug-like molecules. The results are in fair agreement with crystallographic surveys of small molecules as well as of biomolecular complexes and attempt to improve the intuition of chemists when dealing with halogenated compounds.