Qing-Bo Yan, Qing-Rong Zheng, and Gang Su *
College of Physical Sciences, Graduate University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049,
People’s Republic of China
(Received 5 March 2008; revised manuscript received 30 April 2008; published 11 June 2008)
By means of ab initio calculations within the density functional theory, we have found that B80 fullerenes can condense to form stable face-centered-cubic (fcc) solids. It is shown that when forming a crystal, B 80 cages are geometrically distorted, the I h symmetry is lowered to T h , and four boron-boron chemical bonds are formed between every two nearest neighbor B80 cages. The cohesive energy of B80 fcc solid is 0.23 eV/atom with respect to the isolated B 80 fullerene. The calculated electronic structure reveals that the fcc B 80 solid is a metal. The predicted solid phase would constitute a form of pure boron and might have diverse implications. In addition, a simple electron counting rule is proposed, which could explain the stability of B 80 fullerene and the recently predicted stable boron sheet.