Hydrothermal Synthesis and Magnetic Characterization of the Quaternary Oxide CoMo2Sb2O10

The new quaternary layered oxide CoMo 2 Sb 2 O 10 was synthesized by hydrothermal synthesis techniques, and its structure was determined from single-crystal X-ray diffraction data. CoMo 2 Sb 2 O 10 crystallizes in the monoclinic space group C2/c with one Sb 3+ , Mo 6+ , and Co 2+ atom site per unit cell, respectively. The crystal structure contains building units consisting of [Co 2 O 8 ] n , [Mo 2 O 8 ] n , and [SbO 2 ] n chains. These are connected through corner sharing to form charge-neutral [CoMo 2 Sb 2 O 10 ] n layers. Thermal decomposition of CoMo 2 Sb 2 O 10 starts at 550 °C. The magnetic susceptibility follows a Curie-Weiss law above 50 K with a Curie constant of C = 3.46 emu·K·mol -1 corresponding to an effective moment of μ eff = 5.26 μ B per cobalt atom and a Curie-Weiss temperature θ = -13.2 K. Short-range anti-ferromagnetic ordering dominates below 5 K. Magnetic susceptibility and heat capacity data can be successfully modeled by the predictions from an Ising linear chain with an intrachain spin exchange of ca. -7.8 K.