The Largest Metalloid Group 14 Cluster, Ge 18 [Si(SiMe 3 ) 3 ] 6 : An Intermediate on the Way to Elemental Germanium

The oxidation of [Ge 9 (Hyp) 3 ] − (Hyp=Si(SiMe 3 ) 3 ) with an Fe II salt leads to Ge 18 (Hyp) 6 ( 1 ), the largest Group 14 metalloid cluster that has been structurally characterized to date. The arrangement of the 18 germanium atoms in 1 shows similarities to that found in the solid‐state structure Ge(cF136). Furthermore, 1 can be described as a macropolyhedral cluster of two Ge 9 units. Quantum‐chemical calculations further hint at a strained arrangement so that 1 can be considered as a first trapped intermediate on the way from Ge 9 units to elemental germanium with the clathrate‐II structure (Ge(cF136)).