Each of these quadrilateral crystals are about 0.5 cm long on each edge, which is quite big for the sorts of crystals that usually get made in organic chemistry labs

Each of these quadrilateral crystals are about 0.5 cm long on each edge, which is quite big for the sorts of crystals that usually get made in organic chemistry labs. The crystals could grow to such a size because they’re extremely pure. Chip Reisman, a Ph.D. student at the University of Alabama, depends on this high purity for his experiments. The molecule he made has a strained four-membered ring in it (structure shown), which is primed to pop open and attack other four-membered rings to form polymer chains. If this compound isn’t pure enough, then the polymerization reaction doesn’t work and leaves behind a red, waxy solid.

Source: https://cen.acs.org/synthesis/Chemistry-Pictures-Four-sided-molecule/96/web/2018/08