Octahedral clusters molybdenum

Among the most interesting systems are some ternary oxides of lower-valent molybdenum that contain infinite chains of octahedral clusters fused on opposite edges. This type of structure is similar to those found in the lower-halides of... 

We discovered that Chevrel phases, M MogTg, T = S or Se, can insert reversibly two Mg atoms per cluster (i.e. M = Mg, 0cathode materials for secondary Mg batteries [33]. Figure 13.15 shows the basic structure of M MogSg Chevrel phases which comprise octahedral clusters of six molybdenum ions confines in cubes of eight sulfur anions. Between each of two clusters there are 12 sites (two rings of six sites each) for ions insertion, two of which (inner and outer sites) can be occupied... 

Aubert, T. Burel, A. Esnault, M.-A. Cordier, S. Grasset, F. Cabello-Hurtado, F., Root uptake and phytotoxicity of nanosized molybdenum octahedral clusters, J. Hazard. Mater. 219-220 (2012) 111-118. 

Solid-state cluster chemistry is dominated by octahedral (M 5L8)L6 and (MsLi2)L units which are the focus of this paper. These two cluster types are different in the way the metal octahedral core is surrounded by the ligands. In (MsLg)L6-type clusters (Fig. 6.1a), typical for molybdenum and rhenium halides, chalcogenides, and chalcohalides, eight innei hgands (L ) cap the octahedron faces and six outer ligands (L ) are located in the apical positions [9]. For metals with a smaller number of valence electrons, the (M6L i2)L -type clusters... 

Figure If shows the molecular structure of the [Tc6Br6(/t3-Br)5]2- anion. In general, the structure of this anion is similar to the structure of the well-known octahedral halogenide clusters of molybdenum and tungsten [M6X8]4 + (X = Cl,Br, I) [5,8]. The principal difference is that the eight equivalent positions of bridging bromine atoms in the technetium clusters are not fully occupied.

The octahedral metal clusters that have long been familiar features of the lower halide chemistry of niobium, tantalum, molybdenum, and tungsten represent a category of cluster different from those so far considered in that their metal-metal bonding is best treated as involving four AO s on each metal 49, 133,144,165,178). 

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