A structure for ferrocene in which the iron is singly bonded (sigma bonds) to one carbon atom of each cyclopentadiene ligand. Each ring has a delocalised π-bond system in cyclopentadienyl rings which is built from the p_z orbitals on carbon.

an alternative formalization where the iron is "sandwiched" between two cyclopentadiene ligands, with equal binding to all 10 carbon atoms.