HYDROTHERMAL SYNTHESIS OF Pb_2SnO_4

摘要

Fine, yellowish powder of Pb_2SnO_4 with elongated crystalline morphology was synthesized hydrothermally in an alkaline system. To prepare a pure product, the mineralizer NaOH should be at a suitable concentration. In comparison with the solid-state method, the hydrothermal synthesis of Pb_2SnO_4 requires much milder reaction conditions. For some metastable phases such as PbO, 3PbO-H_2O and PbSnO_3-2H_2O transformed into Pb_2SnO_4 with increase in hydrothermal reaction temperature and reaction time. Pb_2SnO_4 is considered to be the thermodynamically stable phase in the alkaline hydrothermal system of PbO and SnO_2. Reaction temperature and reaction time influenced the size and aspect ratio of the elongated particles. In this work, no PbSnO_3 phase was found under any hydrothermal conditions, even though the molar ratio of the starting material was l:l.