A Molecular Orbital Treatment of the Bonding in Certain Metal Atom Clusters

The Crystal Orbital Hamilton Population (COHP) Method as a Tool to Visualize and Analyze Chemical Bonding in Intermetallic Compounds

“…More specifically, the totals of the CBEs are usually obtained by subtracting the numbers of halide ligands from the sums of transition-metal valence electrons. While closed-shell configurations are achieved typically for counts of 16 CBEs in empty octahedral transition-metal clusters whose edges are capped by halide ligands [61], the outcome of the MO-theory-based examinations for the transition-metal-centered rare-earth clusters revealed that closed-shell configurations are accomplished for 18 CBEs ( Figure 2) [56,57]. For instance, a closed-shell configuration is expected for the previously identified [CoY 6 ]I 12 Y, for which an application of the electron-counting scheme yields a total of 18 CBEs (=9 + 7·3 − 12); however, the observed ranges of transition-metals being incorporated in the rare-earth clusters indicate certain electronic flexibilities.…”

Pure and Zn-doped Pt clusters go flat and upright on MgO(100)

“…6,[8][9][10][11][12][13] The electronic structure of clusters is reminiscent of molecules, in that important chemical-physical properties can be understood from a molecular orbital (MO) picture, wherein the MOs will be well-separated in energy, rather than having continuous energy bands. 14,15 The support plays the role of a ligand in very small (o1 nm) clusters, capable of actively modifying cluster structures, charge, and other properties (see e.g. in ref.…”

Preparation and spectra of some hexanuclear niobium halide cluster compounds

“…This result is used as support for using d orbitals in the metal-metal bonding. Mackay and Schneider (8) conclude by agreeing with the general approach of Cotton and Haas (27) and especially by assigning the a2u orbital as the top filled orbital in the 2+ and 3+ clusters.…”

“…The eight bands reported were all assigned as metal-metal transitions according to the scheme of Cotton and Haas (27). Robin and Kuebler (7) obtained electronic spectra of a series of compounds similar to that of Allen and Sheldon (6) in ethanol at room and low temperature.…”

“…Cotton and Haas (27) used an approach similar to that of Grossman ^ al, (26) to calculate the relative energies of the molecular orbitals arising from four metal d orbitals on each atom (dx2_y2 or d^y was considered to be used on bonding only to halogens in the and clusters respectively).…”