LiKCuP2O7: Cation substitution application with mixed-alkaline copper-containing pyrophosphate and magnetic properties

By the application of cation substitution with a site in A–Cu–P–O (A = alkali or mixed-alkali metals) system, a mixed-alkaline metal copper-containing phosphate LiKCuP 2 O 7 has been obtained. Single crystal X-ray diffraction analysis shows that LiKCuP 2 O 7 belongs to the P 2 1 / c space group and features a three-dimensional (3D) network constructed by LiO 4 , KO 9 , CuO 5 , P 2 O 7 units. Interestingly, the CuO 5 polyhedra are interlinked with P 2 O 7 units via vertex-sharing O atoms to form two-dimensional (2D) layers, where the Li + , K + cations reside. In order to understanding the influence of cation size on the 3D networks as well as different dimensions of Cu–P–O frameworks, the structure comparisons in the A–Cu–P–O system have been discussed in detailed. Thermal behavior and infrared spectroscopy have been analysed. What is more, magnetic susceptibility measurements over a wide range of temperature exhibit the presence of antiferromagnetic behaviour.