An all-metal fullerene: [K@Au 12 Sb 20 ] 5

The C 60 fullerene molecule has attracted tremendous interest for its distinctive nearly spherical structure. By contrast, all-metal counterparts have been elusive: Fullerene-like clusters composed of noncarbon elements typically suffer from instability, resulting in more compact geometries that require multiple embedded atoms or external ligands for stabilization. In this work, we present the synthesis of an all-metal fullerene cluster, [K@Au 12 Sb 20 ] 5− , using a wet-chemistry method. The cluster's structure was determined by single crystal x-ray diffraction, which revealed a fullerene framework consisting of 20 antimony atoms. Theoretical calculations further indicate that this distinct cluster exhibits aromatic behavior. The C 60 fullerene molecule has attracted widespread attention for its high-symmetry structure resembling a soccer ball. Xu et al . now report a geometrically similar, fivefold symmetric metal cluster. The compound comprises 12 gold and 20 antimony atoms on the surface that collectively share six delocalized negative charges and enclose a single positive potassium cation in the center. It was prepared by reaction of K 8 SnSb 4 with a gold(I) phosphine complex in ethylenediamine solution and characterized crystallographically as a salt with external cryptand-sequestered potassium ions. —Jake S. Yeston A D5d-symmetric cluster extends fullerene architectures to all-metal compounds.