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 Mo4S4Cl 4, GaMo4S8, and GaMo4S4Te4 has been studied by X-ray electron and emis sion spectroscopy, The results of the investigation revealed that the higher occupied levels (MoMo bonds) contain mainly the d-orbitals of m etal atoms and include also an appreciable contribution from the ligan d orbitals. Upon substitution of Cl by S or Te the covalency of the me tal-bridging ligand bonds is increased. Group theory analysis of orbit al interactions in Mo4S4Cl4 has been performed. A comparison of the re sults of this analysis and the experimental data shows that the M-S an d M-X bonds are many-centered in nature. Based on the experimental dat a obtained a qualitative model of the electronic structure of the vale nce band has been proposed. (C) 1997 Elsevier Science B.V.