A general hydrothermal route to synthesis of nanocrystalline lanthanide stannates: Ln2Sn2O7 (Ln = Y, La–Yb)

A general hydrothermal process with use of lanthanide (III) nitrates and Na2SnO3 as precursors has been proposed for synthesizing nanocrystalline lanthanide stannates with general formula: Ln2Sn2O7 (Ln = Y, La–Yb). Stannates of all lanthanides except for the radioactive promethium were successfully synthesized. Characterization by XRD and TEM revealed that all the products were phase-pure nanocrystalline lanthanide stannates with pyrochlore-type structure. Photoluminescent properties of three samples (i.e. Tb2Sn2O7, Dy2Sn2O7 and Yb2Sn2O7) are also presented. The mole ratio of Ln(NO3)3:Na2SnO3 and hydrothermal temperature were two key factors for this general hydrothermal route.