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Volume 65 
Part 8 
Page i59  
August 2009  

Received 22 June 2009
Accepted 7 July 2009
Online 11 July 2009


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Key indicators
Single-crystal X-ray study
T = 295 K
Mean [sigma](La-O) = 0.006 Å
R = 0.028
wR = 0.076
Data-to-parameter ratio = 20.9
Details

The lanthanum(III) molybdate(VI) La4Mo7O27

Benjamin van der Wolf,a* Peter Helda and Petra Beckera

aInstitute of Crystallography, University of Cologne, 50674 Cologne, Germany
Correspondence e-mail: bvdwolf@uni-koeln.de

Crystals of the orthorhombic phase La4Mo7O27 (lanthanum molybdenum oxide) were obtained from a non-stoichiometric melt in the pseudo-ternary system La2O3-MoO3-B2O3. In the crystal structure, distorted square-antiprismatic [LaO8] and monocapped square-antiprismatic [LaO9] polyhedra are connected via common edges and faces into chains along [010]. These chains are arranged in layers that alternate with layers of [MoO4] and [MoO5] polyhedra parallel to (001). In the molybdate layers, a distorted [MoO5] trigonal bipyramid is axially connected to two [MoO4] tetrahedra, forming a [Mo3O11] unit.

Related literature

The isoformular compounds Eu4Mo7O27 (Naruke & Yamase, 2001[Naruke, H. & Yamase, T. (2001). J. Solid State Chem. 161, 85-92.]) and Gd4Mo7O27 (Naruke & Yamase, 2002[Naruke, H. & Yamase, T. (2002). Acta Cryst. E58, i62-i64.]) have a similar structure, but have monoclinic symmetry. Parameters needed to calculate bond-valence sums from bond lengths were taken from Brown & Altermatt (1985[Brown, I. D. & Altermatt, D. (1985). Acta Cryst. B41, 244-247.]).

Experimental

Crystal data

  • La4Mo7O27

  • Mr = 1659.22

  • Orthorhombic, P c a 21

  • a = 14.1443 (14) Å

  • b = 7.2931 (4) Å

  • c = 22.9916 (13) Å

  • V = 2371.7 (3) Å3

  • Z = 4

  • Mo K[alpha] radiation

  • [mu] = 10.71 mm-1

  • T = 295 K

  • 0.25 × 0.23 × 0.22 mm
Data collection

  • Nonius MACH3 diffractometer

  • Absorption correction: [psi] scan (MolEN; Fair, 1990[Fair, C. K. (1990). MolEN. Enraf-Nonius, Delft, The Netherlands.]) Tmin = 0.841, Tmax = 0.999 (expected range = 0.080-0.095)

  • 17773 measured reflections

  • 7202 independent reflections

  • 6225 reflections with I > 2[sigma](I)

  • Rint = 0.042

  • 3 standard reflections every 100 reflections intensity decay: -4.1%
Refinement

  • R[F2 > 2[sigma](F2)] = 0.028

  • wR(F2) = 0.076

  • S = 1.05

  • 7202 reflections

  • 345 parameters

  • 1 restraint

  • [Delta][rho]max = 2.27 e Å-3

  • [Delta][rho]min = -1.35 e Å-3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 3515 Friedel pairs

  • Flack parameter: 0.039 (14)

Data collection: MACH3 (Enraf-Nonius, 1993[Enraf-Nonius (1993). MACH3 Server Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: MACH3; data reduction: MolEN (Fair, 1990[Fair, C. K. (1990). MolEN. Enraf-Nonius, Delft, The Netherlands.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg, 2005[Brandenburg, K. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2242 ).

Acknowledgements

This work was supported by the Deutsche Forschungsgemeinschaft (DFG) under project BE 2147/6-1&2.

References

Brandenburg, K. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Brown, I. D. & Altermatt, D. (1985). Acta Cryst. B41, 244-247.  [CrossRef] [details]
Enraf-Nonius (1993). MACH3 Server Software. Enraf-Nonius, Delft, The Netherlands.
Fair, C. K. (1990). MolEN. Enraf-Nonius, Delft, The Netherlands.
Flack, H. D. (1983). Acta Cryst. A39, 876-881.  [CrossRef] [ChemPort] [details]
Naruke, H. & Yamase, T. (2001). J. Solid State Chem. 161, 85-92.  [CrossRef] [ChemPort]
Naruke, H. & Yamase, T. (2002). Acta Cryst. E58, i62-i64.  [CrossRef] [details]
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [details]

Acta Cryst (2009). E65, i59  [ doi:10.1107/S1600536809026415 ]

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