Hirshfeld surfaces: A new tool for visualising and exploring molecular crystals

A remarkable new way of exploring molecular crystals is afforded by isosurface rendering of smooth, nonoverlapping molecular surfaces arising from a partitioning of crystal space based on Hirshfeld's stockholder partitioning scheme. These surfaces reflect the proximity of neighbouring atoms and molecules, and hence intermolecular interactions, in a novel visual manner which offers a hitherto unseen picture of molecular shape in a crystalline environment. This work reports 3D isosurface pictures of these molecular surfaces, which we call Hirshfeld surfaces, as well as a number of quantitative measures of molecular size and global shape, applied to a variety of simple molecular crystals. implications for the exploration of crystal packing and crystal engineering are discussed.