title: The Largest Metalloid Group 14 Cluster, Ge18[Si(SiMe3)3]6 : An Intermediate on the Way to Elemental Germanium.
abstract: The oxidation of [Ge9(Hyp)3](-) (Hyp=Si(SiMe3 )3) with an Fe(II) salt leads to Ge18 (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 Ge9 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 Ge9 units to elemental germanium with the clathrate-II structure (Ge(cF136)).
authors.affiliation: Chemistry Department, University Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Kysliak
authors.affiliation: Chemistry Department, University Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
authors.forename: Claudio
authors.initials: C
authors.lastname: Schrenk
authors.affiliation: Chemistry Department, University Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany. andreas.schnepf@uni-tuebingen.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schnepf
keywords: clathrates; germanium; metalloid clusters; quantum-chemical calculations; solid-state structures