Evidence of hollow golden cages

The fullerenes are the first free-standing elemental hollow cages identified by spectroscopy experiments and synthesized in the bulk. Here, we report experimental and theoretical evidence of hollow cages consisting of pure metal atoms, Au-n(-) (n = 16-18); to our knowledge, free-standing metal hollow cages have not been previously detected in the laboratory. These hollow golden cages (bucky gold) have an average diameter > 5.5 angstrom, which can easily accommodate one guest atom inside.