Metal-metal Bond Lengths Research Articles

Metal-metal bond lengths in complexes of transition metals

In complexes of the transition metals containing clusters of metal atoms the cobalt-cobalt bond lengths are almost always within 1 pm of the single-bond value 246 pm given by the enneacovalent radius of cobalt, whereas most of the observed iron-iron bond lengths are significantly larger than the single-bond value 248 pm, the mean being 264 pm, which corresponds to a half-bond. A simple discussion of the structures of these complexes based on spd hybrid orbitals, the electroneutrality principle, and the partial ionic character of bonds between unlike atoms leads to the conclusion that resonance between single bonds and no-bonds would occur for iron and its congeners but not for cobalt and its congeners, explaining the difference in the bond lengths.

Notizen: Dehnung einer Metall-Metall-Bindung durch sterische Hinderung Die Kristallstruktur von FeMn(CO)8P(C6H5)2 / Lengthening of a Metal-Metal-Bond by Steric Hindrance The Crystal Structure of FeMn(CO)8P(C6H5)2 1

The crystal structure of the title complex 1 shows that its metal-metal bond length is not determined by the radii of the metal or phosphorus atoms but by steric hindrance between vicinal carbonyl groups.