Sr2B8: A new member to the σ and π double aromaticity

[Display omitted] •Structures of the Sr2Bn0/− (n = 1–12) clusters were predicted by CALYPSO method.•PES of the Sr2Bn0/− (n = 1–12) clusters have been simulated.•Binding characteristics between atoms of cluster Sr2B8 are analyzed.•It is discussed that Sr2B8 cluster has σ and π double aromaticity. In this paper, we have employed the CALYPSO method to perform structure search on the Sr2Bn0/− (n = 1–12) clusters, resulting in the determination of the global energy minimum structures. Moreover, we have conducted PES simulations on each of the obtained structures with the aim of comparing them to experimental data. Upon comparison, we have identified a relatively more stable inverse sandwich structure Sr2B8, and have conducted an analysis of its internal atomic bonding characteristics. The results indicate that there is a significant transfer of valence electrons from the Sr atoms to the B atoms, leading to the occupied orbitals being predominantly contributed by the valence shell of the B atoms. The B atoms are interconnected by covalent single bonds to form a ring structure, with the two Sr atoms positioned on either side of the B ring, binding to the ring through ionic bonds. The entire Sr2B8 exhibits double aromaticity by the delocalized σ occupied orbitals and the delocalized π occupied orbitals.