Cages and Clusters of the Chalcogens

For example, no less than 12 different formula types are now known for the alkali metal tellurides MxTey [9, 10]. As the total bond order for Te-Te bonds and their opposite secondary Te---Te interactions must remain constant at 1.0, distances di/di will increase in logarithmic dependence on their individual bond order as d3/d4 shorten. Values of d-y/di can range from those of typical single bonds (269-287 pm [10]) to 304 + 9 pm for symmetrical and modestly distorted 3-center 4-electron interactions. 

As will be discussed in Section 2.7.3.1, a number of duster-like non-valence precise Te moieties (n = 4, 6) have also been identified in alkali metal tellurides but these alleviate their electron surplus by participating in asymmetric linear 3- 

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W. S. Sheldrick, Cages and clusters of the chalcogens, in M. Driess and H. Noth (eds.), Molecular Clusters of the Main Group Elements, Wiley-VCH, Weinheim, 2004, pp. 230 15. 

Several chalcogen-bridged clusters of the group 12 metals (Zn, Cd, Hg) have been synthesized utilizing silylated reagents. Mostly, the structures of these complexes are based on adamantane-like cages, and are similar to II-VI clusters synthesized by other approaches, as described in... 

Two studies have been reported in the phosphorus-chalcogen cluster systems. The PjSes molecule (Figure 1) has the same unusual cage structure as PiSs but the compounds are not isostructural. There are two types of P-Se bond, those which form the cage, and which range from 2.21 to 2.30 A,... 

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