Dynamic organic crystals are rapidly gaining traction as a new class of smart materials for energy conversion, however, they are only capable of very small strokes (<12%) and most of them operate through energetically cost-prohibitive processes at high temperatures. We report on the exceptional performance of an organic actuating material with exceedingly large stroke that can reversibly convert energy into work around room temperature. When transitioning at 295–305 K on heating and at 265–275 K on cooling the ferroelectric crystals of guanidinium nitrate exert a linear stroke of 51%, the highest value observed with a reversible operation of an organic single crystal actuator. Their maximum force density is higher than electric cylinders, ceramic piezoactuators, and electrostatic actuators, and their work capacity is close to that of thermal actuators. This work demonstrates the hitherto untapped potential of ionic organic crystals for applications such as light-weight capacitors, dielectrics, ferroelectric tunnel junctions, and thermistors.

Levocetirizine is an orally administrated, second‐generation antihistaminic active pharmaceutical ingredient that has been used to treat symptoms of allergy and long‐term hives for over 25 years. Despite the wide use of this compound, its crystal structure has remained unknown. Here we report the application of 3D electron diffraction (3D ED)/Micro‐crystal electron diffraction (MicroED) to determine the crystal structure of Levocetirizine dihydrochloride directly from crystalline powders that were extracted from commercially available tablets containing the compound. We also showcase the utility of dynamical refinement to unambiguously assign absolute configuration. The results highlight the immense potential of 3D ED/MicroED for structure elucidation of components of microcrystalline mixtures that obviates the need to grow large‐size single crystals and the use of complementary analytical techniques, which could be important for identification as well as for primary structural characterization.

Levocetirizin ist ein oral verabreichtes Antihistaminikum der zweiten Generation, dass seit über 25 Jahren zur Behandlung von Allergiesymptomen und langanhaltender Nesselsucht eingesetzt wird. Trotz der weiten Verbreitung dieser Verbindung war ihre Kristallstruktur bisher unbekannt. Hier berichten wir über die Anwendung der 3D-Elektronenbeugung (3D ED)/Mikrokristallbeugung (MicroED) zur Bestimmung der Kristallstruktur von Levocetirizindihydrochlorid direkt aus kristallinen Pulvern, handelsüblicher Tabletten, die diese Verbindung enthalten. Weiterhin zeigen wir auch den Nutzen der dynamischen Verfeinerung zur eindeutigen Zuordnung der absoluten Konfiguration. Die Ergebnisse unterstreichen das immense Potenzial der 3D-ED/MicroED für die Strukturaufklärung von Komponenten mikrokristalliner Gemische, wodurch sich die Züchtung großer Einkristalle und der Einsatz ergänzender Analysetechniken erübrigt. Dies wird nicht nur dazu beitragen, dass die Methode für die Identifizierung, sondern auch für die primäre strukturelle Charakterisierung neuer Verbindungen in Zukunft an Bedeutung gewinnt.