Peculiar All-Metal s-Aromaticity of the [Au2Sb16]4@ Anion in the

   Gas-phase clusters are deemed to be s-aromatic when they satisfy the 4n + 2 rule of aromaticity for delocalized s electrons and fulfill other requirements known for aromatic systems. While the range of n values was shown to be quite broad when applied to short-lived clusters found in molecularbeam experiments, stability of all-metal cluster-like fragments isolated in condensed phase was previously shown to be mainly ascribed to two electrons (n = 0). In this work, the applicability of this concept is extended towards solid-state compounds by demonstrating a unique example of a storable compound, which was isolated as a stable [K([2.2.2]crypt)]+ salt, featuring a [Au2Sb16] 4@ cluster core possessing two all-metal aromatic AuSb4 fragments with six delocalized s electrons each (n = 1). This discovery pushes the boundaries of the original idea of Kekul8 and firmly establishes the usefulness of the s-aromaticity concept as a general idea for both small clusters and solid-state compounds.