Synthesis, characterization and formation mechanism of dumbbell-like YOHCO3 and rod-like Y2(CO3)3•2.5H2O

A simple hydrothermal route has been used to synthesize orthorhombic YOHCO3 micro-dumbbells and Y-2(CO3)(3)center dot 2.5H(2)O micro-rods without using any surfactant. The as-synthesized products were characterized by X-ray powder diffraction, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential thermal analysis, and elemental analysis. It is found that the final compounds are strongly dependent on the molar ratio of Y(NO3)(3)center dot 6H(2)O to urea. The possible growth mechanisms for dumbbell-like YOHCO3 and rod-like Y-2(CO3)(3)center dot 2.5H(2)O have been proposed. In addition, cubic Y2O3 crystals have been obtained by the thermal conversion of YOHCO3 and Y-2(CO3)(3)center dot 2.5H(2)O at 950 degrees C, which almost inherit their parents' morphologies. (C) 2008 Elsevier B.V. All rights reserved.