Experimental electron density analysis of Mn2(CO)10: metal-metal and metal-ligand bond characterization.

The experimental electron density rho(r) of Mn2(CO)10 was determined by a multipole analysis of accurate X-ray diffraction data at 120 K. The quantum theory of atoms in molecules (QTAM) was applied to rho(r) and its Laplacian [symbol: see text] 2 rho(r). The QTAM analysis of rho(r) showed the presence of a bond critical point (rc); its associated bond path connects the two Mn atoms, but no cross interaction line was found between one manganese and the equatorial carbonyls of the other. The distribution of [symbol: see text] 2 rho(r) indicated "closed-shell" interactions for the metallic Mn-Mn bond and the dative Mn-CO bonds. The values of the topological parameters of the density at rc, rho(rc), [symbol: see text] 2 rho(rc), G(rc) (kinetic energy density), and V(rc) (potential energy density), characterize the bonds and are intermediate to those corresponding to typical ionic and covalent bonds.