Molybdenum cluster compounds electronic structure

The thiohalides MoSX are diamagnetic (269). In Mo4S4Br4, molybdenum transfers 12 electrons to the anions, and 12 electrons remain for the cluster M04, forming a doublet for each edge of the M04 tetrahedron (269). The diamagnetism of the compounds of the type MogCligSe can be interpreted in a similar way (273) from structure considerations. These compounds have been found to be dielectric (273). 

H.-L.Luo Thin-Film Ternary Superconductors. - H.Nohl, W.Klose, O.K Andersen Band Structures of MxMogXg- and M2Mo6X6-Cluster Compounds. - S.D. Bader, S.K.Sinha, B.P.Schweiss, B.Renker Phonons in Ternary Molybdenum Chalcogenide Superconductors. -F.Pobell, D. Rainer, H. Wiihl Electron-Phonon Interaction in Chevrel-Phase Compounds. - Subject Index. 

Our work was initiated on the reduced ternary molybdenum oxides with the thought that the metal cluster electron count (MCE) should be variable for the Mo308 cluster units. Based on Cotton s previous molecular orbital treatment of such clusters (16) it appeared that MCE s from 6 to 8 could be accommodated, but it was not clear whether the seventh and eighth electrons would occupy bonding or antibonding orbitals with respect to the M-M interactions. We thus set about to determine this from structural data on suitable compounds. The attempted replacement of Zn2+ with Sc3+ to secure the compound ZntSc°Mo308 was conducted via the reaction shown in equation 1. 

Our relatively innocent venture into the chemistry of molybdenum oxide systems has led to the discovery of a whole new class of ternary oxide compounds dominated in their structural features by strong metal-metal interactions. Interest in the question of whether the trinuclear clusters in the well known compound Zn.Mo 0 (10, 11) could accept more than 6 electrons in the metal-... 

As used here cluster refers to molecules that contain at least 3 metal atoms and electron configurations suitable for the formation of metal-metal bonds. Molybdenum readily forms strong homoleptic metal-metal bonds seeHomoleptic Compound) and so it is not surprising that molybdenum is readily incorporated into cluster structures see Polynuclear Organometallic Cluster Complexes. 

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