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 al koxide will be described as an efficient synthetic route for the preparatio n of a stoichiometric BaTiO3 powder. During the thermal treatment of the co rresponding precursor a barium-titanium oxycarbonate appears as an intermed iate. High resolution electron microscopy (HREM) and electron energy loss s pectroscopy (EELS) at ionization edges (ELNES), along with X-ray powder dif fractometry (XRD), Fourier-transformed infrared spectroscopy (FTIR), and th ermoanalytical measurements provide evidence of the existence of such an ox ycarbonate phase. The comparison of the measured EEL spectra with quantum-m echanical calculations using density functional theory (DFT) reveals that t his intermediate phase is characterized by an electronic C-Ti interaction i n the crystal lattice and a specific modification of the carbonate bond. (C ) 2000 Elsevier Science Ltd. All rights reserved.