Chapter 8: Structural and Magnetic Studies of Cobalt Phosphonates Check Access

Metal phosphonates have gained increasing attention owing to their potential applications in such fields as catalysis, absorption and separation, proton conductivity, photochemistry, magnetism, and biotechnology, etc. Among the variety of metal phosphonates, cobalt phosphonates are rather interesting because they can display versatile architectures with a wide range of colors arising from different geometries of cobalt ions such as octahedral, tetrahedral, square pyramidal, trigonal-bipyramid, and square-planar, etc. Such compounds are also magnetically important because the octahedrally coordinated Co^II with ⁴T_1g ground state is magnetically high anistropic due to spin-orbit coupling, which lead to very interesting magnetic behaviors such as single molecule magnet, single chain magnet, canted antiferromagnetism, ferrimagnetism, and ferromagnetism, etc. A search of the CCDC database reveals that there are over 139 cobalt phosphonates reported in the literature. In this review, we shall describe the structures and magnetic properties of cobalt phosphonates in detail.