 By contrast, Ru3(CO)12 and Os3(CO)12 adopt D3h-symmetric structures, wherein all 12 CO ligands are terminally bound to the metals.Spectroscopic evidence indicates that the two carbonyl groups may be unsymmetrical, in which case the idealized C2v symmetry is reduced to C2.In solution Fe3(CO)12 is fluxional, resulting in equivalencing all 12 CO groups.