Chalcogens act as inner and outer heteroatoms in borane cages with possible consequences for σ-hole interactions
Chalcogen bonds are a subset of σ-hole interactions and the number of their applications has been increasing rapidly. While chalcogen bonding in organic compounds has been intensively studied in the past decade, it is entirely new in boron cluster chemistry. In this paper, we review the remarkable ability of chalcogenated boron clusters to form strong chalcogen bonds. Chalcogen atoms have a unique property to be incorporated in a boron cluster both innerly and outerly. Various molecular shapes (e.g. icosahedral, bicapped-square antiprismatical) have been computationally analyzed and discussed. No general physical trend has been observed and, therefore, it is recommended to tackle each cluster individually.