Pressure-induced structural transformations in lanthanide titanates: La2TiO5 and Nd2TiO5
The structure of orthorhombic rare earth titanates of La 2TiO5 and Nd2TiO5, where Ti cations are in five-fold coordination with oxygen, has been studied at high pressures by X-ray diffraction (XRD), Raman scattering measurements, and quantum mechanical calculations. Both XRD and Raman results indicated two pressure-induced phase transitions during the process. An orthorhombic super cell (a×b×2c) formed at a pressure between 6 and 10 GPa, and then transformed to a hexagonal high-pressure phase accompanied by partial decomposition. The hexagonal high-pressure phase is quenchable. Detailed structural analysis indicated that the five-coordinated TiO5 polyhedra remain during the formation of super cell, but the orthorhombic-to-hexagonal phase transition at high pressures is a reconstructive process, and the five-fold TiO coordination increased to more than 6. This phase transition sequence was verified by quantum mechanical calculations. © 2010 Elsevier Inc. All rights reserved.
Publication Source (Journal or Book title)
Journal of Solid State Chemistry
Zhang, F., Wang, J., Lang, M., Zhang, J., & Ewing, R. (2010). Pressure-induced structural transformations in lanthanide titanates: La2TiO5 and Nd2TiO5. Journal of Solid State Chemistry, 183 (11), 2636-2643. https://doi.org/10.1016/j.jssc.2010.09.014