Theoretical search for potential candidates as building blocks of hyperhalogens: BS2 and CrO4 molecules

Abstract

Previous works have shown that hyperhalogens can be created by changing the building blocks from halogens to superhalogens, e.g. hyperhalogens (Cu(BO₂)₂, Na(BO₂)₂ and Au(BO₂)₂) are created by replacing halogens of superhalogens MX₂ (M = Cu, Na and Au; X = F, Cl and Br) with the superhalogen BO₂, which has a higher electron affinity of 4.46 eV. Thus we explore the possibility of creating new hyperhalogens by using BS₂ and CrO₄ as building blocks. Our results show that although both BS₂ and CrO₄ are superhalogens, just as BO₂ is, among their dimers only (CrO₄)₂ is a superhalogen, while (BS₂)₂ is not. When a Au atom is decorated with BO₂, BS₂ or CrO₄, we found that Au(BO₂)₂ and Au(BS₂)₂ clusters can be termed hyperhalogens as their respective EA is larger than their corresponding building block BO₂ and BS₂, while Au(CrO₄)₂ is not. This is because the extra electron charge mostly goes to high electronegative BO₂ and BS₂ in anionic Au(BO₂)₂ and Au(BS₂)₂ clusters, while in anionic Au(CrO₄)₂ the extra charge is primarily located on the Au site. Moreover, the study of the interaction of superhalogen BS₂ with Li or K atoms further confirms the ability of BS₂ to act as a building block for hyperhalogens. The calculated fragmentation energies indicate that all of the clusters are stable against any fragmentation.