Solvothermal growth of vaterite in the presence of ethylene glycol, 1,2-propanediol and glycerin

By employing ethylene glycol, 1,2-propanediol and glycerin as the solvents, reaction of calcium chloride with urea in a solvothermal condition (100-150degreesC) produced phase-pure vaterite. This route was convenient and no additives or elaborating pH control were needed. The products show spherulite morphology, which were in nanoscale. The metastable vaterite crystals were analyzed by X-ray powder diffraction, scanning electronic microscope, transmission electron microscopy, infrared techniques, thermogravimetric analysis and differential thermal analysis. In the solvothermal process, the solvent plays an important role in the growth of vaterite crystal. The polyols were found not only acting as the promoter in vaterite formation but also as the stabilizer of this metastable phase. (C) 2002 Elsevier Science B.V. All rights reserved.