Post by Rüdiger W. Seidel

Colour polymorphism is a relatively rare phenomenon in molecular crystals. By serendipity and thanks to my pharmacist colleague Lisa Müller's astute observation, we discovered two concomitant colour polymorphs of (Z)-N-(4-fluoro­phen­yl)-2-oxo­propane­hydrazonoyl chloride and elucidated their crystal structures by X-ray crystallography, using Hirshfeld atom refinement. We have dedicated the article to the memory of the late Professor George M. Sheldrick. I am grateful to my long-time crystallographer colleague Dr Richard Goddard of Max-Planck-Institut für Kohlenforschung and Dr Petra Frohberg of Martin-Luther-Universität Halle-Wittenberg for the great collaboration. Thanks are also due to Peter Bamfaste of Mettler-Toledo International Inc. for his help with the project. https://lnkd.in/eTHtBdwg