An Organometallic\nErbium Bismuth Cluster Complex Comprising\na Bi<sub>6</sub><sup>6–</sup> Zintl Ion

An organometallic\nerbium bismuth cluster complex, [K(THF)<sub>4</sub>]<sub>2</sub>[Cp*<sub>2</sub>Er<sub>2</sub>Bi<sub>6</sub>]\n(<b>1</b>), featuring a heterometallocubane core was isolated.\nThe\ncube emerges from the rare Bi<sub>6</sub><sup>6–</sup> Zintl\nion, bridging two erbium centers for the first time. SQUID magnetometry\nand <i>ab initio</i> calculations uncovered dominant antiferromagnetic\ncoupling enabled through the chair-like hexabismuth anion. The gained\ninsight will promote the design of future polynuclear magnetic molecules\ncomprising prolate lanthanide ions.