Chalcogen Bond: A Sister Noncovalent Bond to Halogen Bond

A sister noncovalent bond to halogen bond, termed chalcogen bond, is defined in this article. By selecting the complexes H2CS center dot center dot center dot Cl-, F2CS center dot center dot center dot Cl-, OCS center dot center dot center dot Cl-, and SCS center dot center dot center dot Cl- as models, the bond-length change, interaction energy, topological property of the electron charge density and its Laplacian, and the charge transfer of the chalcogen bond have been investigated in detail theoretically. It was found that the similar misshaped electron clouds of the chalcogen atom and the halogen atom result in the similar properties of the chalcogen bond and the halogen bond. Experimental results are in good agreement with the theoretical predictions.