  This paper presents for the first time the exact structures at the atomic
level of two important nanomaterials, boron nitride and coronene. Both these
compounds are hexagonal layer structures similar to graphene in two dimensions
and to graphite in three-dimensions. However, they have very different
properties: whereas graphene is a conductor, h-BN is an electrical insulator
and coronene is a polycyclic aromatic hydrocarbon of cosmological interest. The
atomic structures presented here for boron nitride, coronene and graphene have
been drawn to scale based on bond lengths as sums of the atomic radii.
