K4CuO2Cl2: A new alkali metal copper oxyhalide via aqueous solution processes

Abstract

The study of mixed-anion compounds, aimed at combining the advantages of different anions, has been extensively studied. Metal oxyhalides, with a view to combining the benefits of oxides and halides, play a crucial role in numerous advanced scientific and technological fields. Here we present a novel K₄CuO₂Cl₂ compound whose structure was studied via single-crystal X-ray diffraction. The synthesis of the K₄CuO₂Cl₂ compound employs a low-temperature aqueous solution method, in contrast to the high-temperature synthesis of K₄Cu₄OCl₁₀. The crystal structure of K₄CuO₂Cl₂ crystallizes in space group P4₂/mnm with tetragonal symmetry. Moreover, the K atom exhibits a tetrahedral coordination whilst Cu atom have a quadrilateral plane coordination in K₄CuO₂Cl₂, in contrast to the exclusively tetrahedral coordination found in K₄Cu₄OCl₁₀. This unique structural feature is expected to impart distinctive magnetic properties.