Getting Stuffed Improves Stability Of Boron Fullerenes

Adding to the growing theoretical collection of boron analogs of fullerenes, chemists have postulated that a new family of boron clusters stuffed with a few extra boron atoms should be more stable than the previously hypothesized champion of stability, B₈₀. Because boron in many ways resembles carbon in its properties—except in having one fewer electron—chemists have long been intrigued by the possibilities of creating graphitelike and fullerene-like boron materials. Chemists are still working out how to make the compounds, so most research in the area is done on a computer. Eluvathingal D. Jemmis at the Indian Institute of Science, in Bangalore, India, and colleagues used density functional theory to determine the electronic structure and geometries of buckyball-esque boron clusters (Phys. Rev. Lett. 2008, 100, 165504). Their clusters are built upon a base unit of B₈₄, rather than B₈₀. B₈₄ is a ball-shaped framework with an icosahedral B₁₂ unit inserted in the middle. The B₈₄ model has the same symmetry as the C₆₀ fullerene, but B₈₄ requires 50 more electrons to make it stable. By distributing additional boron atoms at various sites around the B₈₄ molecule, the authors found several configurations—from B₉₈ to B₁₀₂—that are predicted to have greater stability than B₈₀.