Study of the electronic structure of polymeric cubane cluster compounds Mo4S4Cl4, GaMo4S8, and Ga4Mo4S4Te4 by X-ray electron and emission spectroscopy

The electronic structure of polymeric cubane cluster compounds Mo4S4Cl4, GaMo4S8, and GaMo4S4Te4 has been studied by X-ray electron and emission spectroscopy, The results of the investigation revealed that the higher occupied levels (MoMo bonds) contain mainly the d-orbitals of metal atoms and include also an appreciable contribution from the ligand orbitals. Upon substitution of Cl by S or Te the covalency of the metal-bridging ligand bonds is increased. Group theory analysis of orbital interactions in Mo4S4Cl4 has been performed. A comparison of the results of this analysis and the experimental data shows that the M-S and M-X bonds are many-centered in nature. Based on the experimental data obtained a qualitative model of the electronic structure of the valence band has been proposed. (C) 1997 Elsevier Science B.V.