Inorganic pentaprismane : The unusual structure of the anion Co@Ge10]3?, which was obtained by the reaction of K4Ge9 with Co(C8H12)(C8H13)] in ethylenediamine, raises questions about chemical bonding in the anion. The Zintl ion cluster has virtual D5h symmetry and is a unique example of a ligand‐free cluster that is not a deltahedron. The delocalized chemical bonding is represented in the picture by one of the bonding orbitals of the anion.
