Geometric solid state chemistry

A while ago I posted about the incredibly rich crystal structure of boron which has a unit cell of hundreds of atoms.
Today at IISER-TVM Jemmis gave me a nice overview of his work [see this paper] showing how this and the associated defect structures emerge naturally from several building blocks including B_12 icosahedra which turn out to be particularly stable.
One call also make fruitful analogies with Huckel type rules associated with aromatic molecules such as benzene.

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