B10M2 (M = Rh, Ir): finally a stable boron-based icosahedral cluster

Abstract

The putative global minimum of clusters with formula B₁₀M₂ (M = Rh, Ir) corresponds to icosahedral structures formed by two alternately stacked B₅ rings with the metals located at the top and bottom vertices. These structures are the closest approximation of molecular clusters to the elusive icosahedral boron. A detailed analysis of the chemical bonding revealed that the covalent character between the transition metal and the boron framework as well as the strong delocalization throughout the structure enhances the stabilization of the icosahedral form.