Institute of Physics, University Duisburg-Essen, Duisburg, Germany.
J Phys Condens Matter. 2012 Aug 1;24(30):305401. doi: 10.1088/0953-8984/24/30/305401. Epub 2012 Jul 4.
The established structure of α-rhombohedral boron, based on one B(12) icosahedron per unit cell only, is put in question. A careful evaluation of the IR-active phonons in comparison with B(6)O, B(4.3)C and β-rhombohedral boron makes it evident that-aside from the B(12) icosahedra-the α-rhombohedral boron structure also contains single boron atoms. We assume these single atoms replace the currently assumed inter-icosahedral three-centre-bonds by covalently saturating the outward directing bonds of the equatorial atoms of the three adjacent icosahedra. Indeed, the implied structure formula B(12)B(2) is not supported by previous density measurements. The IR-phonon spectra of the related structures are correlated and merely shifted relative to one another; significant features depend quantitatively on the actual structure, but they can be easily allocated.
α-菱形硼的既定结构，仅基于每个单位晶胞一个 B(12) 二十面体，正受到质疑。与 B(6)O、B(4.3)C 和 β-菱形硼的 IR 活性声子的仔细比较，表明除了 B(12)二十面体之外，α-菱形硼结构还含有单个硼原子。我们假设这些单个原子通过共价饱和三个相邻二十面体的赤道原子的外向指向键，取代了目前假定的二十面体间三中心键。实际上，所暗示的结构公式 B(12)B(2) 不被先前的密度测量支持。相关结构的 IR 声子谱相互关联并仅相互偏移；显著特征在数量上取决于实际结构，但它们可以轻松分配。
