Closo deltahedral skeleton

There are boron hydrides in which one or more of the polyhedral sites is truly removed. Figure 3-26b shows the systematics of borane polyhedral fragments as obtained from closo boranes, after Williams [3-27] and Rudolph [3-24]. All the faces of the polyhedral skeletons are triangular, and thus the polyhedra may be termed deltahedra and the derived fragments deltahedral. The starting deltahedra are the tetrahedron, the trigonal bipyramid, the octa-... 

A deltahedral doso-cluster with nine atoms n=9) corresponds to a tricapped trigonal prism and Djh point group symmetry (Eigure 3.1c) if 2w + 2 = 20 ske are available for the cluster skeleton bonding. Hence, a cluster with a twofold negative charge, [Eg] , is appropriate for a closo-cluster, and [Eg]" is on par with a nido-duster due to 2n + 4 = 22 ske, forming a C4v-symmetric monocapped square antiprism... 

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