Deltahedral fragment skeletal shapes

Figure 3.1. Deltahedral and deltahedral fragment skeletal shapes of typical closo, nido, and arachno boranes and carboranes.

Entries in the second column of Figure 3.1 and in Figures 3.3 and 3.4 show the deltahedral fragment skeletal shapes most commonly encountered among boranes and carboranes of formulae B H +4, CB iH +3, C2B 2H +2, and so on, all of which can be regarded as derived from hypothetical anions [B H ]4 by protonation and/or isoelectronic replacement of B by C. Their molecular formulae are sometimes written as CxB H +4, where x + y = n, the total number of skeletal atoms. The skeletal structures of these nido species. 

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