A Step in Between: [Sn3Bi3]5− and Its Structural Relationship to [Sn3Bi5]3− and [Sn4Bi4]4

Extraction of “RbSnBi” in liquid ammonia yielded the cluster anion [Sn3Bi5]3−, which could be crystallized in the compound [Rb@[2.2.2]crypt]3[Sn3Bi5]⋅8.87 NH3. This anion is found to be derived from the formerly reported [Sn4Bi4]4− by the formal substitution of one tin atom by bismuth. In contrast, the extraction of “RbSn2/Rb3Bi2” in liquid ammonia yielded the anion [Sn3Bi3]5− in the compound Rb6[Sn3Bi3][Sn4]1/4⋅6.75 NH3. The structural correlation of the two novel clusters indicates that [Sn3Bi3]5− might be an intermediate of the reaction pathway to [Sn3Bi5]3− and [Sn4Bi4]4−. Each cluster is investigated by means of the electron localization function and further characterization was performed by using ESI‐MS. Cage fight: The new crown‐like [Sn3Bi3]5− anion can be seen as the missing link between the also new [Sn3Bi5]3− anion and the previously reported [Sn4Bi4]4− anion. Both cages are formally derived by capping the crown with either a Bi−Bi or a Sn−Bi dumbbell. The main structural and electronic features of the fragment are conserved, especially the three‐center bond of the Sn triangle.