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Volume 69 
Part 4 
Page i19  
April 2013  

Received 17 January 2013
Accepted 26 February 2013
Online 6 March 2013

Key indicators
Single-crystal X-ray study
T = 293 K
Mean [sigma](Ti-O) = 0.004 Å
R = 0.024
wR = 0.027
Data-to-parameter ratio = 49.7
Details
Open access

Redetermination of Nd2Ti2O7: a non-centrosymmetric structure with perovskite-type slabs

aAdvanced Ceramics Research Center, Nagoya Institute of Technology, Asahigaoka 10-6-29, Tajimi 507-0071, Japan,bInstitute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan, and cSchool of Materials Science & Engineering, Inner Mongolia University of Technology, Hohhot 010051, People's Republic of China
Correspondence e-mail: ishizawa@nitech.ac.jp

Single crystals of dineodymium(III) dititanium(IV) heptaoxide, Nd2Ti2O7, were synthesized by the flux method and found to belong to the family of compounds with perovskite-type structural motifs. The asymmetric unit contains four Nd, four Ti and 14 O-atom sites. The perovskite-type slabs are stacked parallel to (010) with a thickness corresponding to four corner-sharing TiO6 octahedra. The Nd and Ti ions are displaced from the geometrical centres of respective coordination polyhedra so that the net polarization occurs along the c axis. The investigated crystals were all twinned and have a halved monoclinic unit cell in comparison with the first structure determination of this compound [Scheunemann & Müller-Buschbaum (1975[Scheunemann, K. & Müller-Buschbaum, H. (1975). J. Inorg. Nucl. Chem. 37, 2261-2263.]). J. Inorg. Nucl. Chem. 37, 2261-2263].

Related literature

For previous determinations of Nd2Ti2O7, see: Scheunemann & Müller-Buschbaum (1975[Scheunemann, K. & Müller-Buschbaum, H. (1975). J. Inorg. Nucl. Chem. 37, 2261-2263.]); Harvey et al. (2005[Harvey, E. J., Whittle, K. R., Lumpkin, G. R., Smith, R. I. & Redfern, S. A. T. (2005). J. Solid State Chem. 178, 800-810.]). For related compounds, see: Gasperin (1975[Gasperin, M. (1975). Acta Cryst. B31, 2129-2130.]); Ishizawa et al. (1980[Ishizawa, N., Marumo, F., Iwai, S., Kimura, M. & Kawamura, T. (1980). Acta Cryst. B36, 763-766.]); Schmalle et al. (1993[Schmalle, H. W., Williams, T., Reller, A., Linden, A. & Bednorz, J. G. (1993). Acta Cryst. B49, 235-244.]). For the extinction method, see: Becker & Coppens (1974[Becker, P. J. & Coppens, P. (1974). Acta Cryst. A30, 129-147.]).

Experimental

Crystal data
  • Nd2Ti2O7

  • Mr = 496.2

  • Monoclinic, P 1121

  • a = 7.6747 (1) Å

  • b = 13.0025 (2) Å

  • c = 5.4640 (1) Å

  • [gamma] = 98.5165 (5)°

  • V = 539.24 (2) Å3

  • Z = 4

  • Mo K[alpha] radiation

  • [mu] = 21.77 mm-1

  • T = 293 K

  • 0.11 × 0.08 × 0.07 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (TWINABS; Bruker, 2008[Bruker (2008). APEX2, SAINT and TWINABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.134, Tmax = 0.206

  • 25187 measured reflections

  • 6608 independent reflections

  • 6200 reflections with I > 3[sigma](I)

  • Rint = 0.049

Refinement
  • R[F2 > 2[sigma](F2)] = 0.024

  • wR(F2) = 0.027

  • S = 1.37

  • 6608 reflections

  • 133 parameters

  • [Delta][rho]max = 2.44 e Å-3

  • [Delta][rho]min = -1.57 e Å-3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 3019 Friedel pairs

  • Flack parameter: 0.220 (12)

Data collection: APEX2 (Bruker, 2008[Bruker (2008). APEX2, SAINT and TWINABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2008[Bruker (2008). APEX2, SAINT and TWINABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007[Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786-790.]); program(s) used to refine structure: JANA2006 (Petrícek et al., 2006[Petrícek, V., Dusek, M. & Palatinus, L. (2006). JANA2006. Institute of Physics, Praha, Czech Republic.]); molecular graphics: ATOMS (Dowty, 2006[Dowty, E. (2006). ATOMS. Shape Software, Kingsport, Tennessee, USA.]) and DIAMOND (Brandenburg & Putz, 2005[Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2720 ).


Acknowledgements

This work was supported by JSPS KAKENHI grant No. 22360272.

References

Becker, P. J. & Coppens, P. (1974). Acta Cryst. A30, 129-147.  [CrossRef] [details]
Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Bruker (2008). APEX2, SAINT and TWINABS. Bruker AXS Inc., Madison, Wisconsin, USA.
Dowty, E. (2006). ATOMS. Shape Software, Kingsport, Tennessee, USA.
Flack, H. D. (1983). Acta Cryst. A39, 876-881.  [CrossRef] [details]
Gasperin, M. (1975). Acta Cryst. B31, 2129-2130.  [CrossRef] [details] [ISI]
Harvey, E. J., Whittle, K. R., Lumpkin, G. R., Smith, R. I. & Redfern, S. A. T. (2005). J. Solid State Chem. 178, 800-810.  [ISI] [CrossRef] [ChemPort]
Ishizawa, N., Marumo, F., Iwai, S., Kimura, M. & Kawamura, T. (1980). Acta Cryst. B36, 763-766.  [CrossRef] [details] [ISI]
Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786-790.  [ISI] [CrossRef] [ChemPort] [details]
Petrícek, V., Dusek, M. & Palatinus, L. (2006). JANA2006. Institute of Physics, Praha, Czech Republic.
Scheunemann, K. & Müller-Buschbaum, H. (1975). J. Inorg. Nucl. Chem. 37, 2261-2263.  [CrossRef] [ChemPort] [ISI]
Schmalle, H. W., Williams, T., Reller, A., Linden, A. & Bednorz, J. G. (1993). Acta Cryst. B49, 235-244.  [CrossRef] [ISI] [details]
Spek, A. L. (2009). Acta Cryst. D65, 148-155.  [ISI] [CrossRef] [details]
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.  [ISI] [CrossRef] [ChemPort] [details]


Acta Cryst (2013). E69, i19  [ doi:10.1107/S1600536813005497 ]

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