Carboranes five-vertex

Although polyhedral carboranes having as few as five and as many as twelve vertices (fourteen if metal atoms are included) are known, [2] most research and applications have centered on the exceptionally stable 7- and 12-vertex cage systems. Largely for reasons of accessibility, the 12-vertex C2B10H12 icosa-hedral carboranes have been most widely studied. The three known isomers, in which the carbon atoms occupy ortho (1,2), meta (1,7), or para (1,12) vertices (Fig. la-c), are... 

The deltahedra found in the deltahedral boranes are illustrated in Figure 17. All of these deltahedra have only degree four and degree five vertices except for one degree six vCTtex in the eleven-vertex edge-coalesced icosahedron found, for example, in and the corresponding carborane... 

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