Rice Sallyport | The Magazine of Rice University | Fall 2007

Bucky’s Big Brother

By Mark Passwaters

It’s bigger, it’s bolder, and it’s boron.

A new study by Boris Yakobson, professor of mechanical engineering and materials science and of chemistry, and his associates Nevill Gonzalez Szwacki and Arta Sadrzadeh, predicts the existence and stability of another buckyball molecule consisting entirely of boron atoms. The paper was an editor’s selection in the April 20 issue of Physical Review Letters.

The boron buckyball is structurally similar to the original buckyball, a cage-shaped molecule of 60 carbon atoms, but it has an additional atom in the center of each hexagon, which significantly increases stability. “This is the first prediction of its possible existence,” Yakobson said of the boron buckyball, or B80. “This has not been observed or even conceived of before. We hope it may lead to a significant breakthrough.”
In the earliest stages of its work, the team attempted to build a buckyball using silicon atoms but determined that it would collapse on itself. The search for another possible atom led the researchers on a short trip across the periodic table.
“One reason we tried boron was because it is one atomic unit from carbon,” Yakobson said. “Boron also has the ability to stick together better than other atoms, which made it even more appealing.”

Initial work with 60 boron atoms failed to create a hollow ball that would hold its form, so another boron atom was placed in the center of each hexagon for added stability.

Yakobson said it is too early to speculate whether the boron buckyball will prove to be as useful as its Nobel Prize-winning sibling. “All we know,” he said, “is that it’s a very logical, very stable structure and likely to exist. It opens up a whole new continent to explore. There should be a strong effort to find it experimentally. That may not be an easy path, but we gave them a good road map.”

Following the paper’s acceptance, there was some debate with the journal’s editors about whether the structure could be termed a buckyball. Yakobson mentioned this to Robert Curl, co-discoverer of the original buckyball along with Harold Kroto and the late Richard Smalley.

“Bob said with a chuckle that it was more of a buckyball than his buckyball,” Yakobson said, adding that C60 was named for famed architect Buckminster Fuller because the molecule looked like conjoined geodesic domes, a structure Fuller invented. “When Fuller made his domes, he made them from triangles because hexagons would collapse,” Yakobson explained. “C60 is made up of hexagons, but in B80, we fill the hexagon with one more atom, making triangles.”