Au$_{20}$ ($^{t}$ Bu$_{3}$ P)$_{8}$: A Highly Symmetric Metalloid Gold Cluster in Oxidation State 0

Metalloid gold clusters have unique properties with respect to size and structure and are key intermediates in studying transitions between molecular compounds and the bulk phase of the respective metal. In the following, the synthesis of the all-phosphine protected metalloid cluster Au$_{20}$ ($^{t}$ Bu$_{3}$ P)$_{8}$, solely built from gold atoms in the oxidation state of 0 is reported. Single-crystal X-ray analysis revealed a highly symmetric hollow cube-octahedral arrangement of the gold atoms, resembling gold bulk structure. Quantum-chemical calculations illustrated the cluster can be described as a 20-electron superatom. Optical properties of the compound have shown molecular-like behavior.