New balls, please!

Scientists in China have identified an exceptionally stable volleyball-shaped molecular cluster, which they have dubbed ‘volleyballene’. The hollow cage arrangement contains 20 scandium atoms arranged in octagons and 60 carbon atoms in pentagons to give a bulbous configuration.

volleyball (right)

The Sc20C60 nanocluster's structure viewed as space-filling model (middle) looks similar to a

Nanoscale metal–carbon clusters attract tremendous interest due to their unique properties and anticipated use in electronics and catalysis. In addition to C60 buckminsterfullerene, scientists have proposed a variety of metallo–carbohedrenestructures but volleyballene is the first one spiked with scandium atoms.

The team led by Ying Liu at Hebei Normal University looked at six molecular structures featuring different combinations of carbon pentagons and scandium atoms. They minimised their energies and although extensively deformed, the optimised structures tended to have a common feature: Sc8C10 subunits. Volleyballene Sc20C60 possessed the lowest energy, making it the most energetically favourable of the configurations considered. Each subunit has two carbon pentagons surrounded by one scandium octagon and six subunits unite in a wraparound pattern resembling that of volleyball. With a relatively large HOMO­–LUMO gap of 1.471eV, volleyballene could serve as an interesting, and very stable, buckyballene variant.

If synthesised, volleyballene might house other atoms and molecules, and be used to study fundamental chemistry.