Soluble polyhedral Zintl ions of group-14 elements

3 Soluble polyhedral Zintl ions of group-14 elements 

Excluding the elements Si, P, As, cp = crypt n = number of cluster atoms group number found in Zintl phases found in solution number of skeletal electrons, 2n + 2 closo- and 2n + 4 nido-type disorder Hg disordered over the comers of the trigonal prism centered with TP+ T1 2 centered with Na+ Tli2 centered with Mg +-Hg + Au-Au bond, does not follow Wade s rules, four and nine atom clusters of group 14 elements (see Table 3 and Table 5). 

NaSi NaGe NaSn NaPb KSn KPb RbSn RbPb CsSn CsPb  

Whereas use of ammonia as the extraction solvent led to amorphous solids, the use of ethylenediamine resulted in the isolation of crystalline materials such as Na4(en)sGe9 and Na3(en)4Sbv and led to the first crystal-structure determination of the polyanion in Na4(en)7Sn9.f Finally, the introduction of the crown 

In addition to titration methods, the solutions have been characterized on the basis of the composition of the precursor alloys, color, and occasionally by NMR methods (Table 4). The structures of mixed-cluster anions of group-14 elements are only poorly characterized. °° ° Mixed anions such as Sn Pbg j, (0 . Y 9) can be synthesized electrochemically by using a 1 1 Sn/Pb alloy as the cathode. All nine-atom clusters are fluxional in solution. 

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