Hydrothermal Synthesis and Magnetic Characterization of the Quaternary Oxide CoMo₂Sb₂O₁₀

The new quaternary layered oxide CoMo₂Sb₂O₁₀ was synthesized by hydrothermal synthesis techniques, and its structure was determined from single-crystal X-ray diffraction data. CoMo₂Sb₂O₁₀ crystallizes in the monoclinic space group C2/c with one Sb³⁺, Mo⁶⁺, and Co²⁺ atom site per unit cell, respectively. The crystal structure contains building units consisting of [Co₂O₈]_n, [Mo₂O₈]_n, and [SbO₂]_n chains. These are connected through corner sharing to form charge-neutral [CoMo₂Sb₂O₁₀]_n layers. Thermal decomposition of CoMo₂Sb₂O₁₀ 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.