Nanocrystalline serrabrancaite (MnPO4·H2O) prepared by a simple precipitation route at low temperature

MnPO4·H2O was precipitated from manganese nitrate tetrahydrates and phosphoric acid in the presence of water–ethanol system at low temperature. The precipitates were characterized by TG/DTG/DTA, XRD, scanning electron microscope (SEM), FTIR and UV–vis–near IR techniques. The presence of ethanol in the spontaneous precipitation process of serrabrancaite leads to highly crystalline powder. Thermal treatment at 600 °C yields a crystalline manganese pyrophosphate (Mn2P2O7). The particle sizes obtained from X-ray line broadening are 66 ± 28 and 54 ± 18 nm for the MnPO4·H2O and Mn2P2O7, respectively. FTIR spectrum of MnPO4·H2O is assigned base on the PO43− ion and water molecules in the structure. The diffuse reflectance spectrum revealed that MnPO4·H2O presents a strong Jahn-Teller effect, which is in agreement with the crystal structure.