Electron delocalization in a non-cyclic all-metal III–V cluster

In this report, we apply the concept of delocalization of electrons in a chain structure to an all-metal system using experimental (photoelectron spectroscopy, velocity map imaging) and first principles theoretical investigations. We show that In2Bi− is a triatomic cluster anion with a bent structure, where bismuth is the bridging atom between the two indium atoms. It is found that 6p-electrons (2π and 4σ) are delocalized over the cluster. The In–Bi bond lengths in In2Bi− are identical to bond lengths of In3Bi, which is an all-metal aromatic system analogue to Al3Bi, and are shorter than the rest of InxBi(−) clusters, showing the presence of a higher bond order.