New evidence for an oxycarbonate phase as an intermediate step in BaTiO3 preparation

A newly developed method of spray hydrolysis of a barium-titanium double alkoxide will be described as an efficient synthetic route for the preparation of a stoichiometric BaTiO3 powder. During the thermal treatment of the corresponding precursor a barium-titanium oxycarbonate appears as an intermediate. High resolution electron microscopy (HREM) and electron energy loss spectroscopy (EELS) at ionization edges (ELNES), along with X-ray powder diffractometry (XRD), Fourier-transformed infrared spectroscopy (FTIR), and thermoanalytical measurements provide evidence of the existence of such an oxycarbonate phase. The comparison of the measured EEL spectra with quantum-mechanical calculations using density functional theory (DFT) reveals that this intermediate phase is characterized by an electronic C-Ti interaction in the crystal lattice and a specific modification of the carbonate bond. (C) 2000 Elsevier Science Ltd. All rights reserved.