Crystalline yttrium oxycarbonate, Y2O2CO3, Was synthesized by our original flux method using the 0.476Li(2)CO(3)-0.270Na(2) CO3-0.254K(2)CO(3) eutectic mixture at 450 degrees C. The oxycarbonate was characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and Fourier-transfer infrared spectroscopy (FT-IR). The Y2O2CO3 prepared by the flux method was a crystalline single phase of hexagonal rare earth oxycarbonate (type-It). This is the first report on the single-phase synthesis of crystalline hexagonal type-II Y2O2CO3. (c) 2005 Elsevier Inc. All rights reserved.