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 is 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. HREM and EELS at ionisation edges (ELNES), along with XRD, 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 reveals that this intermediate phase is characterised by an electronic C-Ti interaction in the crystal lattice and a specific modification of the carbonate bond. 24 refs.