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Volume 69 
Part 2 
Page i6  
February 2013  

Received 27 November 2012
Accepted 14 December 2012
Online 12 January 2013

Key indicators
Single-crystal X-ray study
T = 296 K
Mean [sigma](S-O) = 0.002 Å
R = 0.022
wR = 0.045
Data-to-parameter ratio = 15.3
Details
Open access

Schaurteite, Ca3Ge(SO4)2(OH)6·3H2O

aDepartment of Geosciences, University of Arizona, Tucson, AZ 85721, USA
Correspondence e-mail: moriglie@email.arizona.edu

This report presents the first crystal structure determination of the mineral schaurteite, ideally Ca3Ge(SO4)2(OH)6·3H2O, tricalcium germanium bis(sulfate) hexahydroxide trihydrate. This single-crystal X-ray diffraction study investigated a natural sample from the type locality at Tsumeb, Namibia. Schaurteite is a member of the fleischerite group of minerals, which also includes fleischerite, despujolsite, and mallestigite. The structure of schaurteite consists of slabs of Ca(O,OH,H2O)8 polyhedra (site symmetry mm2) interleaved with a mixed layer of Ge(OH)6 octahedra (-3m.) and SO4 tetrahedra (3m.). There are two H atoms in the asymmetric unit, both located by full-matrix refinement, and both forming O-H...O hydrogen bonds.

Related literature

For the original description of schaurteite, see: Strunz & Tennyson (1967[Strunz, H. & Tennyson, C. (1967). Festschrift Dr. Werner T. Schaurte, pp. 33-47. Neuss-Rhein, Germany: Bauer & Schaurte.]). For descriptions of related minerals: fleischerite (Frondel & Strunz, 1960[Frondel, C. & Strunz, H. (1960). Neues Jahrb. Mineral. Monatsh. 1960, 132-142.]); despujolsite (Gaudefroy et al., 1968[Gaudefroy, C., Granger, M. M., Permingeat, F. & Protas, J. (1968). Bull. Soc. Fr. Minéral. Cristallogr. 91, 43-50.]); mallestigite (Sima et al., 1996[Sima, I., Ettinger, K., Koppelhuber-Bitschnau, B., Taucher, J. & Walter, F. (1996). Mitteilungen der Österreichischen Mineralogischen Gesellschaft, 141, 224-225.]). For structural refinements of related minerals: despujolsite (Barkley et al., 2011[Barkley, M. C., Yang, H., Evans, S. H., Downs, R. T. & Origlieri, M. J. (2011). Acta Cryst. E67, i47-i48.]); fleischerite (Otto, 1975[Otto, H. H. (1975). Neues Jahrb. Mineral. Abh. 123, 160-190.]). For analysis of anisotropic displacement parameters, see: Downs (2000[Downs, R. T. (2000). Rev. Mineral. Geochem. 41, 61-88.]).

Experimental

Crystal data
  • Ca3Ge(SO4)2(OH)6(H2O)3

  • Mr = 541.05

  • Hexagonal, P 63 /m m c

  • a = 8.5253 (4) Å

  • c = 10.8039 (6) Å

  • V = 680.03 (6) Å3

  • Z = 2

  • Mo K[alpha] radiation

  • [mu] = 3.79 mm-1

  • T = 296 K

  • 0.05 × 0.03 × 0.03 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2005[Sheldrick, G. M. (2005). SADABS. University of Göttingen, Germany.]) Tmin = 0.656, Tmax = 0.747

  • 17243 measured reflections

  • 536 independent reflections

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

  • Rint = 0.061

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

  • wR(F2) = 0.045

  • S = 1.15

  • 536 reflections

  • 35 parameters

  • All H-atom parameters refined

  • [Delta][rho]max = 0.40 e Å-3

  • [Delta][rho]min = -0.42 e Å-3

Table 1
Hydrogen-bond geometry (Å, °)

D-H...A D-H H...A D...A D-H...A
O3-H1...O2i 0.73 (3) 2.12 (3) 2.823 (2) 164 (3)
O4-H2...O1ii 0.79 (3) 2.04 (3) 2.789 (2) 158 (3)
Symmetry codes: (i) y, x, -z; (ii) [y, -x+y, z+{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2004[Bruker (2004). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). 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: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: XtalDraw (Downs & Hall-Wallace, 2003[Downs, R. T. & Hall-Wallace, M. (2003). Am. Mineral. 88, 247-250.]); software used to prepare material for publication: SHELXL97.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BR2217 ).


Acknowledgements

The authors thank the Arizona Science Foundation for their support. Thanks to Stephen G. West for systems support. This paper benefited greatly from the comments of Sean Parkin, who recognized the likehood of centrosymmetry in schaurteite.

References

Barkley, M. C., Yang, H., Evans, S. H., Downs, R. T. & Origlieri, M. J. (2011). Acta Cryst. E67, i47-i48.  [CrossRef] [details]
Bruker (2004). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.
Bruker (2005). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Downs, R. T. (2000). Rev. Mineral. Geochem. 41, 61-88.  [CrossRef]
Downs, R. T. & Hall-Wallace, M. (2003). Am. Mineral. 88, 247-250.  [ChemPort]
Frondel, C. & Strunz, H. (1960). Neues Jahrb. Mineral. Monatsh. 1960, 132-142.
Gaudefroy, C., Granger, M. M., Permingeat, F. & Protas, J. (1968). Bull. Soc. Fr. Minéral. Cristallogr. 91, 43-50.  [ChemPort]
Otto, H. H. (1975). Neues Jahrb. Mineral. Abh. 123, 160-190.
Sheldrick, G. M. (2005). SADABS. University of Göttingen, Germany.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.  [CrossRef] [details]
Sima, I., Ettinger, K., Koppelhuber-Bitschnau, B., Taucher, J. & Walter, F. (1996). Mitteilungen der Österreichischen Mineralogischen Gesellschaft, 141, 224-225.
Strunz, H. & Tennyson, C. (1967). Festschrift Dr. Werner T. Schaurte, pp. 33-47. Neuss-Rhein, Germany: Bauer & Schaurte.


Acta Cryst (2013). E69, i6  [ doi:10.1107/S1600536812050945 ]

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