D ∞h B 2 (BS) 2 −/2− and T d B(BS) 4 − : Boron sulfide clusters containing BB multiple bonds and B − tetrahedral centers

A density functional theory investigation on the geometrical and electronic properties of B 4 S   2 0/−/2−(B 2 (BS)   2 0/−/2− ) and B 5 S   4 0/−(B(BS)   4 0/− ) clusters has been performed in this work. Both the doublet B 2 (BS)   2 −([SBBBBS] − ) (D ∞h , 2 Π u ) and the singlet B 2 (BS)   2 2−([SBBBBS] 2− ) (D ∞h , 1 Σ   g + ) proved to have perfect linear ground‐state structures containing a multiply bonded BB core (BB or BB) terminated with two BS groups, while T d B(BS)   4 −turned out to possess a perfect B − tetrahedral center directly corrected to four BS groups, similar to the corresponding boron hydride molecules of D ∞h B 2 H   2 − , D ∞h B 2 H   2 2− , and T d BH   4 − , respectively. B 4 S 2 and B 5 S 4 neutrals, however, appeared to be much different: they favor a planar fan‐shaped C 2v B 4 S 2 (a di‐S‐bridged B 4 rhombus) and a planar kite‐like C 2v B 5 S 4 (a di‐S‐bridged B 3 triangle bonded to two BS groups), respectively. One‐electron detachment energies and symmetrical stretching vibrational frequencies are calculated for D ∞h B 2 (BS)   2 −and T d B(BS)   4 −monoanions to facilitate their future characterizations. Neutral salts of B 2 (BS) 2 Li 2 with an elusive BB triple bond and B(BS) 4 Li containing a tetrahedral B − center are predicted possible to be targeted in experiments. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010