JETP Letters: issues online

This study explores the oxidation dynamics of "pure" CuCl during prolonged environmental exposure through X-ray diffraction and temperature-dependent magnetization assessments. While CuCl is traditionally considered diamagnetic, our investigation reveals the emergence of an antiferromagnetic transition at 4.7 K. This anomaly is potentially induced by the integration of water molecules into the CuCl matrix. The hydration process initiates a series of oxidation reactions, ultimately transmuting CuCl into Cu₂Cl(OH)₃. Over time, the distinctive diffractogram peaks corresponding to CuCl diminish, concurrently with the appearance and intensification of those ascribed to Cu₂Cl(OH)₃, culminating in a complete phase transition as confirmed by X-ray analysis. Correspondingly, magnetization measurements clearly discern magnetic transitions at 6.4 and 16 K, intensifying with the sample's exposure duration. These findings illuminate the stark potential for probing the magnetic intricacies of Cu₂Cl(OH)₃, a subject that remains a compelling and unresolved intrigue within the field.