Physicist Lai-Sheng Wang of Washington State University and colleagues have produced hollow golden balls, nanoscopic gold clusters composed of just 16, 17 or 18 atoms. Wang worked with the late Rick Smalley at Rice University on the carbon cages that became known as buckyballs. He is one of several scientists that have attempted to make metallic analogues of the all-carbon molecules. "Au-16 is beautiful and can be viewed as the smallest golden cage," Wang says. Topologically the cluster appears as if one had "removed the four corner atoms from the Au-20 pyramid and then letting the remaining atoms relax a little." This results in a hollow cluster into which the researchers will soon try to trap a single atom of another element.