“…[1,2] In the molecular world, there are two examples of face-fused deltahedral boranes,n amely [B 21 H 18 ] À and B 20 H 16 (CH 3 CN) 2 ·(CH 3 CN) in which the [B 21 H 18 ] À is made of two fused B 12 icosahedra (coined as "twinned icosahedra") while B 20 H 16 (CH 3 CN) 2 ·-(CH 3 CN) is composed of aB 12 icosahedron and a nido-B 11 fragment. [3,4] In addition, there are another ten or so examples of face-fused heteroboranes,such as,carboranes,metalloboranes,a nd that is all. [5] Despite this scarcity,h owever,f used clusters,e specially boranes,h ave been of much theoretical interest in order to develop rules for rationalizing their structures,b onding,a nd electron counts.…”