Dianionic clusters electronic properties

Group 13 clusters with electron counts less than the 2n - - 2 electrons corresponding to closo deltahedra have also been described. The classic examples of these are the boron subhalides, B C1 where n = 4, 8 -12 (and a more limited set of bromides and iodides), which have an electron count of 2n and are known as hypercloso clusters. These are based on the same closo structures expected for the 2n - - 2 electron clusters, namely, tetrahedral, dodecahedral, and tricapped trigonal prismatic for n = 4, 8, and 9. The 2n - - 2 dianions B C1 also show the expected deltahedral structures. The stability of the B C1 clusters has been attributed to a combination of the r-donor properties of the halides and steric effects. ... 

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