Seeking Silver Bird for Tiny Golden Cage

In tiny, tiny bits, gold makes exquisite geometry.

Clusters of 20 gold atoms, for example, always come in the shape of a
pyramid, perfect for a subatomic King Tut.

Now scientists have found a new, unexpected configuration: a cage consisting
of just 16 atoms, the smallest hollow piece of 24-karat gold possible.

"The cage structures were not expected, because metal clusters tend
to be more compact," said Lai-Sheng Wang, who is a physicist at
Washington State University and Pacific Northwest National Laboratory.

The gold cage, with gemlike triangular facets, is the metallic equivalent
of buckyballs, molecules consisting of 60 carbon atoms in the shape of
soccer balls that were discovered in 1995. Buckyballs made a splash in
the scientific world and beyond with their novel, but easy to describe
shape. The catchy name helped, too.

Until now, no one has made similar hollow structures out of metals.

Nano-size gold has unusual, useful properties; for one, it acts as a
catalyst for speeding up certain chemical reactions. Dr. Wang was interested
in the way the properties of gold change with size and shape.

The findings will appear in the May 30 issue of The Proceedings of the
National Academy of Sciences.

Next on the agenda, Dr. Wang said, is a ship-in-a-bottle trick. He says
he wants to place some other atom inside the gold cage, which might endow
the cluster with new and different characteristics.

But the golden cages seem unlikely to achieve the fame of buckyballs.
For one thing, Dr. Wang has not thought of a catchy name.

"No, not for this one," he said.

from the New York Times

Empty golden cages? Wedding rings?