Figure 1.

CDO crystallizes in a variety of crystal forms. (a): example of a twinned crystal which was observed in a number of drops under a variety of conditions. X-ray diffraction analysis of this polycrystalline crystal form confirmed the presence of multiple lattices (data not shown). (b), (c) and (d): examples of the most common CDO crystal morphologies. Needles very often formed in drops in tree-shaped (b) or fan-shaped (c) structures originating from single points of nucleation and at times were also found as long thin single crystals (d). (e) and (f): the cube-shaped morphology shown here yielded the highest resolution diffraction data, including the 1.5 Å data outlined in this report.