Boron balls

US researchers have predicted the existence and stability of another “buckyball” consisting entirely of boron atoms.

A new study by Boris Yakobson, professor of mechanical engineering and materials science and of chemistry at Rice University, and his associates Nevill Gonzalez Szwacki and Arta Sadrzadeh predicts the existence and stability of another “buckyball” consisting entirely of boron atoms.

The original buckyball, a cage-shaped molecule of 60 carbon atoms, was discovered at Rice by Robert Curl, Harold Kroto and Richard Smalley in 1985. The boron buckyball is structurally similar to the original C60 fullerene, but it has an additional atom in the centre 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 do hope it may lead to a significant breakthrough.’

In the earliest stages of their work, the team attempted to build a “buckyball” using silicon atoms but determined that it would collapse on itself. Their search for another possible atom led them on a short trip across the periodic table.

‘Boron is nearby (one atomic unit from carbon). One reason we tried it was because of proximity,” Yakobson said. ‘Boron also has the ability to ‘catenate’, to stick together better than other atoms, which also made it appealing.’

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

Yakobson estimated that the scientific work, the consideration of the variety of boron clusters to single out the B80, took more than a year, with Szwacki initially leading the work and then Sadrzadeh gradually taking greater part in the effort.

‘We thought we had the answer, essentially, after three or four months, but then we had to prove it,’ Yakobson said. ‘There are numerous possibilities, but we had to prove that this was the answer. I think we’ve made a convincing case.’

Yakobson said it is too early to speculate whether the boron buckyball will prove to be equally or more useful than its Nobel Prize-winning sibling.

‘It’s too early to make comparisons,’ he said. ‘All we know is that it’s a very logical, very stable structure likely to exist.’