Octadecahedron

Ball-and-stick model of the octadecahedral closo-undecaborate ion, [B11H11]2−, as found in the crystal structure of the benzyltriethylammonium salt.[1]

In geometry, an octadecahedron (or octakaidecahedron) is a polyhedron with 18 faces. No octadecahedron is regular; hence, the name does not commonly refer to one specific polyhedron.

In chemistry, "the octadecahedron" commonly refers to a specific structure with C2v symmetry, the edge-contracted icosahedron, formed from a regular icosahedron with one edge contracted. It is the shape of the closo-boranate ion [B11H11]2−.

  1. ^ O. Volkov; W. Dirk; U. Englert; P. Paetzold (1999). "Undecaborates M2[B11H11]: Facile Synthesis, Crystal Structure, and Reactions". Z. Anorg. Allg. Chem. 625 (7): 1193–1200. doi:10.1002/(SICI)1521-3749(199907)625:7<1193::AID-ZAAC1193>3.0.CO;2-L.