Symmetry Collapse due to the Presence of Worm-Aromaticity in Ge244-

In this work, we synthesized and isolated a continuous 24-atom cluster Ge244−, which was characterized by X-ray diffraction analysis and Energy-dispersive X-ray spectroscopy, showing an elongated worm-like structural characteristic. Theoretical analysis reveals that electron delocalization plays a vital role in the formation and stabilization of the prolate cluster. In contrast with carbon atoms, 4s orbitals of Ge-atoms do not easily hybridize with 4p orbitals and s-type lone-pairs could be localized with high occupancy. Thus, there are not enough electrons to form a stable symmetrical fullerene-like structure such as C24 fullerene. Three aromatic units with two [Ge9] and one [Ge6] species, connected by classical 2c-2e Ge-Ge σ-bonds, have been aligned together forming three independent shielding cones (worm-aromaticity) and eventually caused a collapse of the global symmetry of the prolate cluster.