Stone–Wales Transformations

Buckminsterfullerene is a molecule shaped like a soccer ball, made of 60 carbon atoms. If one of the bonds between two hexagons rotates, we get a weird mutant version of this molecule:

This is an example of a Stone-Wales transformation: a 90° rotation in a so-called ‘π bond’ between carbon atoms. Here’s how it works in graphene:

Graphene is a sheet of carbon molecules arranged in hexagons. When they undergo a Stone–Wales transformation, we get a Stone–Wales defect with two pentagons ...