Ln₂□Ti₂O₇ (Ln = La, Nd, Sm, Gd): a novel series of defective Ruddlesden–Popper phases formed by topotactic dehydration of HLnTiO₄⁺‡

Abstract

Topotactic dehydration of HLnTiO₄ (Ln = La, Nd, Sm or Gd) around 480–500 °C yields a new series of metastable layered perovskite oxides, Ln₂□Ti₂O₇, that possess a defective Sr₃Ti₂O₇ structure, where the cubooctahedral sites within the double-perovskite layers are most likely vacant.

References

1. A. R. Wells, Structural Inorganic Chemistry, Clarendon Press, Oxford, 5th edn., 1984.
2. S. N. Ruddlesden and P. Popper, Acta Crystallogr., 1957, 10, 538; 1958, 11, 54.
3. J. G. Bednorz and K. A. Müller, Z. Phys. B, 1986, 64, 189.
4. Y. Moritomo, A. Asamitsu, H. Kuwahara and Y. Tokura, Nature, 1996, 380, 141; R. Seshadri, C. Martin, M. Herien, B. Raveau and C. N. R. Rao, Chem. Mater., 1997, 9, 270; P. D. Battle, M. A. Green, N. S. Laskey, J. E. Millburn, L. Murphy, M. J. Rosseinsky, S. P. Sullivan and J. F. Vente, Chem. Mater., 1997, 9, 552.
5. J. Gopalakrishnan and V. Bhat, Inorg. Chem., 1987, 26, 4299.
6. T. Takata, Y. Furumi, K. Shinohara, A. Tanaka, M. Hara, J. N. Kondo and K. Domen, Chem. Mater., 1997, 9, 1063.
7. G. Blasse, J. Inorg. Nucl. Chem., 1968, 30, 656; G. Blasse and G. P. M. Van den Heuvel, J. Solid State Chem., 1974, 10, 206.
8. S. H. Byeon, K. Park and M. Itoh, J. Solid State Chem., 1996, 121, 430; K. Toda, Y. Kameo, S. Kurita and M. Sato, J. Alloys Comp., 1996, 234, 19.
9. N. S. P. Bhuvanesh and J. Gopalakrishnan, J. Mater. Chem., 1997, 7, 2297.
10. S. H. Byeon, J. J. Yoon and S. O. Lee, J. Solid State Chem., 1996, 127, 119.
11. P. M. Gasperin, Acta Crystallogr., Sect. B, 1975, 31, 2129.
12. M. A. Subramaian, G. Aravamudan and G. V. Subba Rao, Prog. Solid State Chem., 1983, 15, 55.