Synthesis of Layered Sodium Manganese Phosphate via Low-heating Solid State Reaction and Its Properties

The layered nanocrystalline sodium manganese phosphate was synthesized by low‐heating solid state reaction using MnSO₄·H₂O and Na₃PO₄·12H₂O as raw materials. The resulting sodium manganese phosphate and its calcined products were characterized using element analysis, thermogravimetry and differential thermal analyses (TG/DTA), Fourier transform IR (FT‐IR), X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), ultraviolet‐visible (UV‐Vis) absorption spectroscopy, and magnetic susceptibility. The results showed that the product obtained at 70°C for 3 h, NaMnPO₄·3H₂O, was a layered compound, and its crystallite size and interlayer distance were 27 nm and 1.124 nm, respectively. The thermal process of NaMnPO₄·3H₂O between room temperature and 700°C experienced three steps, the dehydration of the one adsorption water at first, and then dehydration of the two crystal waters, at last crystallization of NaMnPO₄. Magnetic susceptibility measurements of NaMnPO₄· 3H₂O from room temperature to 2.5 K point to ferrimagnetic ordering at T_N‐35 K.