Structure and bonding in the omnicapped truncated tetrahedral Au20 cluster: analogies between gold and carbon cluster chemistry.

The proposed omnicapped truncated tetrahedral structure of the recently reported Au20 cluster can be generated from a regular dodecahedron by forming two transannular Au-Au bonds across each face while preserving T symmetry. An electron-precise chemical bonding scheme accounts for the large band gap (1.77 eV) of Au20 and relates its structure to that of titanacarbohedrene Ti8C12 and Os20(CO)40(2)-. Copyright 2004 American Chemical Society