Chalcogenides bonding

Thallium(I) thiolates form polymers, often with complex structures. Thus TlSPh is ionic and best described as [Tl7(SPh)6]+[Tl5(SPh)6], while TISBu is an octameric cage.58 Numerous anionic polychalcogenide complexes are known, such as [Tl2Te2]2 and [T12(S4)2]2 (6-XXV).59 As expected for a soft metal, Tl—chalcogenide bonds are strong and highly covalent. 

Lower formal oxidation states are stabilized, however, by M-M bonding in ternary chalcogenides such as M MeQn, M4M6Q13 (M = alkali metal M = Re, Tc Q = S, Se) and the recently reported M gMeS. Their structures are all based on the face-capped, octahedral MeXg cluster unit found in Chevrel phases (p. 1018) and in the dihalides of Mo and W... 

Crystal chemistry of the chalcogenides and pnictides of transition elements. F. Hulliger, Struct. Bonding (Berlin), 1968,4, 83-229 (532). 

Just as, in Group VB, niobium, so, in this Group, molybdenum provides most of the examples of the chalcogenide halides. The occurrence and preparation of such compounds are described in numerous publications. In most cases, they have been obtained as powders, with the composition based on chemical analyses only. The presence of defined, homogeneous phases is, therefore, in many cases doubtful. In addition, some published results are contradictory. A decision is possible where a complete structure analysis has been made. As will be shown later, the formation of metal-metal bonds (so-called clusters), as in the case of niobium, is the most characteristic building-principle. Such clusters... 

Metal-Metal Bonds in Molybdenum Chalcogenide Halides... 

InSCl, InSBr, InSeCl, and InSeBr are isotypic, and crystallize in the hexagonal CdCU lattice type. The halide and chalcogenide ions are statistically distributed among the Cl sites. As in CdClj, the bonding within the InYs Xa/a octahedra should be predominantly ionic 162). 

Group-IIIB-group-IIIB bonds feature in the low-valent chalcogenides of Al, Ga and In shown in Table 1. These involve [Al—Al] ", [Ga—Ga], [In—In] or [In—In—In] in the solid state. The discrete compounds are synthesized by heating stoichiometric mixtures of the metal and S, Se or Te, typically in evacuated quartz... 

Chen L, Xia SQ, Corbett JD (2005) Metal-rich chalcogenides. Synthesis, structure, and bonding of the layered Lui]Te4. Comparison with the similar ScgTe3 and HnSe4. Inorg Chem 44 30573062... 

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