Another Au32 gold fullerene: a novel spherical cage cluster with octahedral symmetry

Abstract

The discovery of C₆₀ opened the window to the development of numerous fullerene clusters, with non-covalent gold clusters emerging as one of the most fascinating class. Notably, the icosahedral (I_h) Au₃₂ cluster, the first reported metal fullerene, has attracted significant attention due to its high symmetry and stable hollow-cage structure. In this study, we report the discovery of a novel Au₃₂ hollow-cage fullerene structure exhibiting octahedral (O_h) symmetry. This configuration demonstrates remarkable stability with a substantial HOMO–LUMO energy gap. Theoretical analysis reveals that the O_h cage can stably encapsulate up to four additional gold atoms within its framework. A systematic exploration of the O_h cage structure with all elements led to the identification of a series of stable endohedral fullerene clusters. In total, 30 stable hollow cage structures with the O_h symmetry are identified, including Au₃₂, Ag₃₂, Cu₃₂, B₃₂, and Si₃₂. This work offers insights into the cage structures of fullerene clusters and advances the fundamental understanding of all-metal-element fullerenes.