The first "free-standing" elemental hollow cages - structures that would rival "buckyballs" but be made of an element other than carbon - have been reported. Researchers at the University of Nebraska, Washington State University and the Pacific Northwest National Laboratory (PNNL) in Washington State have presented experimental and theoretical evidence for cage-like structures made only of gold atoms, dubbed "bucky gold".
Carbon buckyballs - or fullerenes - with a hollow structure of 60 carbon atoms were discovered in the 1980s. Now the researchers in the US seem to have made the first metallic version. These structures have only 16 to 18 atoms and form a structure made from triangles - more like a gem than a football. They have average diameters of more than 5.5 Å and could hold a guest atom inside, although the researchers have yet to attempt this. Applications could exploit the fact that at the scale of atoms, gold becomes highly reactive and is a very good catalyst.
Further reading
Satya Bulusu, Xi Li, Lai-Sheng Wang and Xiao Cheng Zeng 2006 Proc. Natl. Acad. Sci. 103 22 8326.