Study of Oxygen−Nitrogen Replacement in BaTiO₃ by ¹⁴N Solid-State Nuclear Magnetic Resonance

We here report about oxygen−nitrogen substitution in the anionic sublattice of BaTiO 3 by calcination in a NH 3 flow at 950 °C. The resulting oxynitride BaTi(O,N) 3 is shown to possess cubic structure by powder XRD and to contain 0.57 mass percent of nitrogen by hot gas extraction analysis. Solid-state 14 N-NMR is used to characterize the electronic surroundings of the N 3- anions in the oxynitride. Analysis of 14 N-NMR line shapes as well as comparison of line positions to those of TiN and BaTaO 2 N implies that the incorporated nitrogen anions do indeed occupy the oxygen sites in the BaTi(O,N) 3 lattice. The study illustrates the usefulness of solid-state NMR as a method for tracking ion substitution in highly symmetric environments, such as perovskite-structured oxynitrides, because of its high sensitivity to symmetry changes in the local electronic surroundings of nuclei.