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Volume 69 
Part 12 
Page i84  
December 2013  

Received 12 September 2013
Accepted 19 November 2013
Online 23 November 2013

Key indicators
Single-crystal X-ray study
T = 296 K
Mean [sigma](As-O) = 0.004 Å
R = 0.022
wR = 0.044
Data-to-parameter ratio = 24.5
Details
Open access

The P43 enanti­omorph of Sr2As2O7

aLaboratoire de Chimie Industrielle, Département de Génie des Matériaux, Ecole Nationale d'Ingénieurs de Sfax Université de Sfax, BP W3038, Sfax, Tunisia, and bLaboratoire de l'Etat Solide, Faculté des Sciences, Université de Sfax, BP W3038, Sfax, Tunisia
Correspondence e-mail: mbarekaicha@yahoo.fr

The crystal structure of strontium diarsenate has been reinvestigated from single-crystal X-ray diffraction data. In contrast to the previous determinations of this structure [Weil et al. (2009[Weil, M., Dordevic, T., Lengauer, C. L. & Kolitsch, U. (2009). Solid State Sci. 11, 2111-2117.]). Solid State Sci. 11, 2111-2117; Edhokkar et al. (2012[Edhokkar, F., Hadrich, A., Graia, M. & Mhiri, T. (2012). Mater. Sci. Eng. 28, 012017.]). Mater. Sci. Eng., 28, 012017] and to all isotypic A2B2O7 compounds that crystallize in the space group P41, the current redetermination revealed the P43 enanti­omorph of Sr2As2O7 with a purity of 96.3 (8)%. The crystal structure is made up from two eclipsed As2O7 diarsenate groups (symmetry 1) with characteristically longer As-O bridging bonds [1.756 (4)-1.781 (4) Å] than the terminal As-O bonds [1.636 (4)-1.679 (4) Å] and four Sr2+ sites with coordination numbers ranging from seven to nine. The building units are arranged in sheets parallel to (001).

Related literature

The crystal structure of Sr2As2O7 has previously been refined from X-ray powder diffraction data (Weil et al., 2009[Weil, M., Dordevic, T., Lengauer, C. L. & Kolitsch, U. (2009). Solid State Sci. 11, 2111-2117.]) in the space group P41 and was later reinvestigated (Edhokkar et al., 2012[Edhokkar, F., Hadrich, A., Graia, M. & Mhiri, T. (2012). Mater. Sci. Eng. 28, 012017.]). For isotypic structures crystallizing in space group P41, see: Baglio & Dann (1972[Baglio, J. A. & Dann, J. N. (1972). J. Solid State Chem. 4, 87-93.]); Webb (1966[Webb, N. C. (1966). Acta Cryst. 21, 942-948.]); Boudin et al. (1993[Boudin, S., Grandin, A., Borel, M. M., Leclaire, A. & Raveau, B. (1993). Acta Cryst. C49, 2062-2064.]); Müller-Bunz & Schleid (2000[Müller-Bunz, H. & Schleid, T. (2000). Z. Anorg. Allg. Chem. 626, 2549-2556.]); Deng & Ibers (2005[Deng, B. & Ibers, J. A. (2005). Acta Cryst. E61, i76-i78.]). For general structural features of the pyroarsenate anion, see: Weil & Stöger (2010[Weil, M. & Stöger, B. (2010). Acta Cryst. B66, 603-614.]).

Experimental

Crystal data
  • Sr2As2O7

  • Mr = 437.08

  • Tetragonal, P 43

  • a = 7.1089 (1) Å

  • c = 25.6160 (4) Å

  • V = 1294.54 (4) Å3

  • Z = 8

  • Mo K[alpha] radiation

  • [mu] = 26.62 mm-1

  • T = 296 K

  • 0.75 × 0.43 × 0.14 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2008[Bruker (2008). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.448, Tmax = 0.751

  • 18524 measured reflections

  • 4930 independent reflections

  • 4593 reflections with I > 2[sigma](I)

  • Rint = 0.035

Refinement
  • R[F2 > 2[sigma](F2)] = 0.022

  • wR(F2) = 0.044

  • S = 1.01

  • 4930 reflections

  • 201 parameters

  • 1 restraint

  • [Delta][rho]max = 0.92 e Å-3

  • [Delta][rho]min = -1.34 e Å-3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 2400 Friedel pairs

  • Absolute structure parameter: 0.037 (8)

Data collection: APEX2 (Bruker, 2008[Bruker (2008). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2008[Bruker (2008). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg, 1999[Brandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.]) and ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2770 ).


References

Baglio, J. A. & Dann, J. N. (1972). J. Solid State Chem. 4, 87-93.  [CrossRef] [ChemPort] [Web of Science]
Boudin, S., Grandin, A., Borel, M. M., Leclaire, A. & Raveau, B. (1993). Acta Cryst. C49, 2062-2064.  [CrossRef] [IUCr Journals]
Brandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Bruker (2008). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Deng, B. & Ibers, J. A. (2005). Acta Cryst. E61, i76-i78.  [CrossRef] [ChemPort] [IUCr Journals]
Edhokkar, F., Hadrich, A., Graia, M. & Mhiri, T. (2012). Mater. Sci. Eng. 28, 012017.
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.  [Web of Science] [CrossRef] [ChemPort] [IUCr Journals]
Flack, H. D. (1983). Acta Cryst. A39, 876-881.  [CrossRef] [IUCr Journals]
Müller-Bunz, H. & Schleid, T. (2000). Z. Anorg. Allg. Chem. 626, 2549-2556.  [CrossRef] [ChemPort]
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [ChemPort] [IUCr Journals]
Webb, N. C. (1966). Acta Cryst. 21, 942-948.  [CrossRef] [ChemPort] [IUCr Journals]
Weil, M., Dordevic, T., Lengauer, C. L. & Kolitsch, U. (2009). Solid State Sci. 11, 2111-2117.  [Web of Science] [CrossRef] [ChemPort]
Weil, M. & Stöger, B. (2010). Acta Cryst. B66, 603-614.  [CrossRef] [ChemPort] [IUCr Journals]


Acta Cryst (2013). E69, i84  [ doi:10.1107/S1600536813031619 ]

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