Fullerene-like Boron Analog Reevaluated

In 2007, scientists announced in a computational study that the most energetically stable form of the B₈₀ cluster was likely a symmetrical hollow cage—a boron analog to the C₆₀ fullerene (C&EN, April 30, 2007, page 28). Upon further investigation, some researchers now conclude that the most stable B₈₀ structural isomer isn’t a hollow cage but an icosahedral B₁₂ cluster (one of the most stable forms of boron) tucked inside an unsymmetrical B₆₈ shell. In the latest report on this front, Zhongfang Chen of the University of Puerto Rico, Río Piedras; Jijun Zhao of China’s Dalian University of Technology; and colleagues have unveiled the lowest energy B₈₀ isomer to date (J. Phys. Chem. A, DOI: 10.1021/jp1018873). Their core-shell model is 1.34 eV more stable than the B₈₀ hollow cage and 1.04 eV more stable than another recently reported core-shell isomer (Chem. Commun. 2010, 46, 3878). “Identifying the core-shell structure as being energetically more favorable will prompt scientists to reexamine previous theoretical work and help initiate a new wave of research on boron clusters and related boron sheets and nanotubes,” Chen says.