Controllable synthesis of polyhedral YF3 microcrystals via a potassium sodium tartrate-assisted hydrothermal route

In the present paper, we reported the successful synthesis of polyhedral yttrium trifluoride (YF3) microcrystals via a simple hydrothermal route, employing yttrium oxide (Y2O3 99.99%), ammonium fluoride (NH4F) as the starting reactants and potassium sodium tartrate (C4H4O6KNa·4H2O) as the structure-directing reagent. The reaction was carried out at 150 °C for 16 h. The phase and morphology of the product were characterized by means of powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), and field emission scanning electron microscopy (SEM). The research results indicated that the pH and K+ ions in the system played crucial roles in the formation of polyhedral YF3 microcrystals. Some factors influencing the morphology of YF3 crystals were investigated, including the reaction temperature, time, and the amounts of initial HNO3, NH4F and C4H4O6KNa·4H2O. A possible growth mechanism of polyhedral YF3 microcrystals is discussed.