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A Labile Hydride Strategy for the Synthesis of Heavily Nitridized BaTiO3



Takeshi Yajima, Fumitaka Takeiri, Kohei Aidzu, Hirofumi Akamatsu, Koji Fujita, Wataru Yoshimune, Masatoshi Ohkura, Shiming Lei, Venkatraman Gopalan, Katsuhisa Tanaka, Craig Brown, Mark Green, Takafumi Yamamoto, Yoji Kobayashi, Hiroshi Kageyama


Oxynitrides, which have been explored extensively in the last decade, exhibit various novel properties beyond oxides, including visible light absorption, photocatalytic activity and high dielectric constants. The synthesis of these oxynitrides generally requires high temperature ammonia treatment (800 °C-1300 ° C) of starting regents (e.g. oxides), but the highly reducing conditions as well as the low mobility of N3- in the lattice put a significant constraint on the compositional/structural versatility and hence resulting properties. Here we describe a novel topochemical synthesis pathway to access an oxynitride using a titanium perovskite oxyhydride as a host. The lability of H- in BaTiO3-xHx (x less than or equal to} 0.6) allows N3-/H- exchange to occur at relatively low temperatures (< 500 °C), yielding BaTiO3-xN2x/3 (via mixed O-N-H intermediates), which is accompanied by a crossover from metallic to insulating behaviour. BaTiO3-xN2x/3 (x ≅ 0.6, 0.4) is tetragonal and exhibits ferroelectricity, with a critical temperature, TC, comparable to BaTiO3. The present results suggest that this "labile hydride" strategy has the potential to open a new avenue for the preparation of various oxynitrides and perhaps other mixed anionic compounds.
Nature Chemistry


neutron scattering, structure


Yajima, T. , Takeiri, F. , Aidzu, K. , Akamatsu, H. , Fujita, K. , Yoshimune, W. , Ohkura, M. , Lei, S. , Gopalan, V. , Tanaka, K. , Brown, C. , Green, M. , Yamamoto, T. , Kobayashi, Y. and Kageyama, H. (2015), A Labile Hydride Strategy for the Synthesis of Heavily Nitridized BaTiO<sub>3</sub>, Nature Chemistry, [online], (Accessed June 1, 2023)
Created November 30, 2015, Updated October 12, 2021