Polymorphism of Scyllo-Inositol:  Joining Crystal Structure Prediction with Experiment to Elucidate the Structures of Two Polymorphs

We report on the crystal structures of two polymorphs of scyllo-inositol. Crystallization of this inositol initially failed to yield a single crystal suitable for structure solution, so a computational prediction of the low-energy forms was performed in parallel with the crystallization experiments. When a single crystal was finally grown, its structure failed to explain the powder X-ray diffraction pattern of the bulk material, which seemed to show a mixture of polymorphs. With the aid of the lowest-energy predicted crystal structure from a lattice energy search and the DASH program for structure solution from powder data, we propose the structure of the second polymorph. The combined use of single-crystal structure solution, structure solution from powder diffraction data, and a lattice energy search for possible structures, which was necessary for the elucidation of the second polymorph of scyllo-inositol, demonstrates the synergy between experimental and computational studies of molecular organic materials.