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Volume 69 
Part 8 
Pages i48-i49  
August 2013  

Received 2 July 2013
Accepted 4 July 2013
Online 10 July 2013

Key indicators
Single-crystal X-ray study
T = 296 K
Mean [sigma](Mg-O) = 0.001 Å
R = 0.031
wR = 0.069
Data-to-parameter ratio = 28.1
Details
Open access

Redetermination of MgCrO4·5H2O

aInstitute for Chemical Technologies and Analytics, Division of Structural Chemistry, Vienna University of Technology, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria
Correspondence e-mail: mweil@mail.zserv.tuwien.ac.at

The CCD-data based redetermination of the crystal structure of the title compound, magnesium chromate(VI) pentahydrate, confirms in principle the previous study based on precession film data [Bertrand et al. (1971[Bertrand, G., Dusausoy, Y., Protas, J. & Watalle-Marion, G. (1971). C. R. Hebd. Seances Acad. Sci. Ser. C, 272, 530-533.]). C. R. Hebd. Seances Acad. Sci. Serie C, 272, 530-533.], but with all atoms refined with anisotropic displacement parameters and with all H atoms localized. This allowed an unambiguous assignment of the hydrogen-bonding pattern. MgCrO4·5H2O adopts the MgSO4·5H2O structure type. It contains two Mg2+ sites on special positions with site symmetry -1, one tetrahedral CrO4 group and five water molecules. Four of them coordinate to the Mg2+ cation, and one is an uncoordinating lattice water molecule. The octahedral environment of the Mg2+ cation is completed by two axial O atoms of CrO4 tetrahedra. This arrangement leads to the formation of chains parallel to [011]. Adjacent chains are linked through O-H...O hydrogen bonds (one of them bifurcated), involving both the coordinating and lattice water molecules, into a three-dimensional network.

Related literature

For the original structure determination of the title compound, see: Bertrand et al. (1971[Bertrand, G., Dusausoy, Y., Protas, J. & Watalle-Marion, G. (1971). C. R. Hebd. Seances Acad. Sci. Ser. C, 272, 530-533.]). For hydrogen-bonding pattern in the structures of MXO4·5H2O compounds (M = Mg, Cu; X = S, Cr), see: Baur & Rolin (1972[Baur, W. H. & Rolin, J. L. (1972). Acta Cryst. B28, 1448-1455.]). For Cr-O bond length distributions in chromates(VI), see: Pressprich et al. (1988[Pressprich, M. R., Willett, R. D., Poshusta, R. D., Saunders, S. C., Davis, H. B. & Gard, H. B. (1988). Inorg. Chem. 27, 260-264.]). For bond lengths and angles in the related structure of MgCrO4·11H2O, see: Fortes et al. (2013[Fortes, A. D., Wood, I. G. & Gutmann, M. J. (2013). Acta Cryst. C69, 324-329.]). For standardization of structure data, see: Gelato & Parthé (1987[Gelato, L. M. & Parthé, E. (1987). J. Appl. Cryst. 20, 139-143.]).

Experimental

Crystal data
  • MgCrO4·5H2O

  • Mr = 230.39

  • Triclinic, [P \overline 1]

  • a = 6.1467 (3) Å

  • b = 6.3742 (4) Å

  • c = 10.7048 (6) Å

  • [alpha] = 75.919 (4)°

  • [beta] = 81.603 (3)°

  • [gamma] = 71.134 (3)°

  • V = 383.92 (4) Å3

  • Z = 2

  • Mo K[alpha] radiation

  • [mu] = 1.59 mm-1

  • T = 296 K

  • 0.10 × 0.08 × 0.01 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2011[Bruker (2011). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.594, Tmax = 0.748

  • 10569 measured reflections

  • 4019 independent reflections

  • 3340 reflections with I > 2[sigma](I)

  • Rint = 0.031

Refinement
  • R[F2 > 2[sigma](F2)] = 0.031

  • wR(F2) = 0.069

  • S = 1.02

  • 4019 reflections

  • 143 parameters

  • 10 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • [Delta][rho]max = 1.17 e Å-3

  • [Delta][rho]min = -0.72 e Å-3

Table 1
Selected bond lengths (Å)

Mg1-OW3 2.0505 (9)
Mg1-OW2i 2.0656 (9)
Mg1-O4ii 2.0952 (9)
Mg2-OW5 2.0265 (10)
Mg2-OW1 2.0467 (8)
Mg2-O1 2.1099 (9)
Cr1-O3iii 1.6357 (9)
Cr1-O4iii 1.6554 (9)
Cr1-O1 1.6568 (9)
Cr1-O2 1.6579 (8)
Symmetry codes: (i) x, y-1, z; (ii) -x+1, -y, -z; (iii) -x+1, -y, -z+1.

Table 2
Hydrogen-bond geometry (Å, °)

D-H...A D-H H...A D...A D-H...A
OW1-HW1A...O2iv 0.81 (2) 1.96 (2) 2.7702 (13) 174 (2)
OW1-HW1B...O3 0.80 (2) 1.97 (2) 2.7598 (13) 169 (2)
OW2-HW2A...O1v 0.79 (2) 2.19 (2) 2.9014 (13) 150 (2)
OW2-HW2A...OW1 0.79 (2) 2.52 (2) 3.1008 (14) 132 (2)
OW2-HW2B...OW4 0.80 (2) 2.02 (2) 2.8173 (12) 171 (2)
OW3-HW3A...O2iii 0.82 (2) 1.97 (2) 2.7891 (13) 170 (2)
OW3-HW3B...OW4vi 0.81 (2) 1.99 (2) 2.7906 (14) 172 (2)
OW4-HW4B...O1iv 0.83 (2) 2.32 (2) 3.1205 (14) 163 (2)
OW4-HW4A...O4 0.80 (2) 2.06 (2) 2.8535 (14) 170 (2)
OW5-HW5B...O2iii 0.80 (2) 1.93 (2) 2.7262 (13) 173 (2)
OW5-HW5A...O3vii 0.79 (2) 1.96 (2) 2.7409 (12) 174 (2)
Symmetry codes: (iii) -x+1, -y, -z+1; (iv) -x+1, -y+1, -z+1; (v) -x, -y+1, -z+1; (vi) -x+1, -y+1, -z; (vii) x-1, y, z.

Data collection: APEX2 (Bruker, 2011[Bruker (2011). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2011[Bruker (2011). APEX2, SAINT and SADABS. 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: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ATOMS for Windows (Dowty, 2008[Dowty, E. (2008). ATOMS for Windows. Shape Software, Kingsport, Tennessee, USA.]); software used to prepare material for publication: 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: BR2229 ).


Acknowledgements

The X-ray centre of the Vienna University of Technology is acknowledged for financial support and for providing access to the single-crystal diffractometer.

References

Baur, W. H. & Rolin, J. L. (1972). Acta Cryst. B28, 1448-1455.  [CrossRef] [ChemPort] [IUCr Journals]
Bertrand, G., Dusausoy, Y., Protas, J. & Watalle-Marion, G. (1971). C. R. Hebd. Seances Acad. Sci. Ser. C, 272, 530-533.  [ChemPort]
Bruker (2011). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
Dowty, E. (2008). ATOMS for Windows. Shape Software, Kingsport, Tennessee, USA.
Fortes, A. D., Wood, I. G. & Gutmann, M. J. (2013). Acta Cryst. C69, 324-329.  [CrossRef] [ChemPort] [IUCr Journals]
Gelato, L. M. & Parthé, E. (1987). J. Appl. Cryst. 20, 139-143.  [CrossRef] [Web of Science] [IUCr Journals]
Pressprich, M. R., Willett, R. D., Poshusta, R. D., Saunders, S. C., Davis, H. B. & Gard, H. B. (1988). Inorg. Chem. 27, 260-264.  [CrossRef] [ChemPort] [Web of Science]
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [ChemPort] [IUCr Journals]
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.  [Web of Science] [CrossRef] [ChemPort] [IUCr Journals]


Acta Cryst (2013). E69, i48-i49   [ doi:10.1107/S1600536813018588 ]

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