Two-Dimensional Icosahedral B₁₂ Networks in Boron-Rich Crystals

Iwami Higashi and Toshio Ishii

Department of Chemistry, Chiba Institute of Technology, Shibazono, Narashino, Chiba 275-0023, Japan

(Received September 25, 2001; Accepted October 5, 2001)

Keywords: Boron-Rich Solids, B₁₂ Icosahedron, b-Rhomboheral Boron, a-AlB₁₂, YB₆₆

Abstract. Two-dimensional icosahedral B₁₂ networks in boron-rich crystals have been examined on the basis of crystal structure data. The linkages between the icosahedral B₁₂ units within the networks are effected approximately along the five-fold axis of B₁₂ icosahedron. Features of the icosahedral B₁₂ networks as well as the external appearances of individual icosahedral B₁₂ units are discussed in connection with the crystal structure-type in which the B₁₂ networks are present. The crystal phases used for the calculations of icosahedral B₁₂ structures are as follows: a-rhombohedral boron, b-rhombohedral boron, a-tetragonal boron, a-AlB₁₂, g-AlB₁₂, AlMgB₁₄, AlB₂₄C₄, YB₆₆ and YB₄₁Si_1.2.