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Volume 65 
Part 8 
Page i60  
August 2009  

Received 25 June 2009
Accepted 8 July 2009
Online 15 July 2009


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Key indicators
Powder X-ray study
T = 300 K
Mean [sigma](Y-O) = 0.009 Å
R = 0.053
wR = 0.069
Data-to-parameter ratio = 5.5
Details

Rietveld refinement of Y2GeO5

Eric M. Rivera-Muñoza* and Lauro Buciob

aCentro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, AP 1-1010, Queretaro, Qro. 76000, Mexico, and bInstituto de Física, Universidad Nacional Autónoma de México, AP 20-364, 01000 México DF, Mexico
Correspondence e-mail: emrivera@fata.unam.mx

Y2GeO5 (yttrium germanium pentaoxide) was synthesized by solid-state reaction at 1443 K. The arrangement, which has monoclinic symmetry, is isostructural with Dy2GeO5 and presents two independent sites for the Y atoms. Around these atoms there are distorted six-coordinated YO6 octahedra and seven-coordinated YO7 pentagonal bipyramids. The YO7 polyhedra are linked together, sharing their edges along a surface parallel to ab, forming a sheet. Each of these parallel sheets is interconnected by means of GeO4 tetrahedra, sharing an edge (or vertex) on one side and a vertex (or edge) on the other adjacent side. Parallel sheets of YO7 polyhedra are also interconnected by undulating chains of YO6 octahedra along the c axis. These octahedra are joined together, sharing a common edge, to form the chain and share edges with the YO7 polyhedra of the sheets.

Related literature

For the isotypic structure of Dy2GeO5, see: Brixner et al. (1985[Brixner, L. H., Calabrese, J. C. & Chen, H.-Y. (1985). J. Less-Common Met. 110, 397-410.]). Different synthesis methods have been reported for this compound, including preparation by conventional r.f. magnetron sputtering (Minami et al., 2003[Minami, T., Kobayashi, Y., Miyata, T. & Yamazaki, M. (2003). Thin Solid Films, 425, 35-40.]), solid-state reactions at high temperatures (Zhao et al., 2003[Zhao, F., Guo, P., Li, G., Liao, F., Tian, S. & Jing, X. (2003). Mater. Res. Bull. 38, 931-940.]), MOCVD and LSMCD (Natori et al., 2004[Natori, E., Kijima, T., Furuyama, K. & Tasaki, Y. (2004). Eur. Patent No. EP20020738688.]). For bond-valence parameters, see: Brese & O'Keeffe (1991[Brese, N. E. & O'Keeffe, M. (1991). Acta Cryst. B47, 192-197.]), and for the bond-valence model, see: Brown (1981[Brown, I. D. (1981). Structure and Bonding in Crystals, Vol. 2, edited by M. O'Keefe & A. Navrotsky, pp. 1-30. New York: Academic Press.], 1992[Brown, I. D. (1992). Z. Kristallogr. 199, 255-272.]). For oxide phosphors, see: Minami et al. (2001[Minami, T., Yamazaki, M., Miyata, T. & Shirai, T. (2001). Jpn J. Appl. Phys. 40, L864-L866.], 2002[Minami, T., Miyata, T., Ueno, T. & Urano, Y. (2002). US Patent No. 2002/0047515 Al.], 2004[Minami, T., Miyata, T., Ueno, T. & Urano, Y. (2004). US Patent No. 6707249 B2.]). Data used to model the second phase present in the reaction product, Y2Ge2O7, were taken from Redhammer et al. (2007[Redhammer, G. J., Roth, G. & Amthauer, G. (2007). Acta Cryst. C63, i93-i95.]). For related literature on technological applications, see: Fei et al. (2003[Fei, Z., Peimin, G., Guobao, L., Fuhui, L., Shujian, T. & Xiping, J. (2003). Mater. Res. Bull. 38, 931-940.]).

Experimental

Crystal data

  • Y2GeO5

  • Mr = 330.43

  • Monoclinic, I 2/a

  • a = 10.4706 (2) Å

  • b = 6.8292 (1) Å

  • c = 12.8795 (2) Å

  • [beta] = 101.750 (3)°

  • V = 901.66 (3) Å3

  • Z = 8

  • Cu K[alpha] radiation

  • T = 300 K

  • Specimen shape: flat sheet

  • 20 × 20 × 0.2 mm

  • Specimen prepared at 1443 K

  • Particle morphology: spherical, white
Data collection

  • Bruker Advance D8 diffractometer

  • Specimen mounting: packed powder sample container

  • Specimen mounted in reflection mode

  • Scan method: step

  • 2[theta]min = 8.0, 2[theta]max = 80.0°

  • Increment in 2[theta] = 0.02°
Refinement

  • Rp = 0.053

  • Rwp = 0.069

  • Rexp = 0.024

  • S = 2.90

  • Wavelength of incident radiation: 1.540560 Å

  • Profile function: pseudo-Voigt modified by Thompson et al. (1987[Thompson, P., Cox, D. E. & Hastings, J. B. (1987). J. Appl. Cryst. 20, 79-83.])

  • 582 reflections

  • 105 parameters

Data collection: DIFFRAC/AT (Siemens, 1993[Siemens (1993). DIFFRAC/AT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.]); cell refinement: DICVOL91 (Boultif & Louëer 1991[Boultif, A. & Louër, D. (1991). J. Appl. Cryst. 24, 987-993.]); data reduction: FULLPROF (Rodríguez-Carvajal, 2006[Rodríguez-Carvajal, J. (2006). FULLPROF. URL: http://www.ill.eu/sites/fullprof/ php/reference.html.]); method used to solve structure: coordinates taken from an isotypic compound (Brixner et al., 1985[Brixner, L. H., Calabrese, J. C. & Chen, H.-Y. (1985). J. Less-Common Met. 110, 397-410.]); program(s) used to refine structure: FULLPROF; molecular graphics: ATOMS (Dowty, 2000[Dowty, E. (2000). ATOMS for Windows. Shape Software, Kingsport, Tennessee, USA.]); software used to prepare material for publication: FULLPROF.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BR2110 ).

Acknowledgements

The authors acknowledge the collaboration of Manuel Aguilar Franco for performing the conventional X-ray diffraction measurements, and projects CONACyT SEP-2007-81700.

References

Boultif, A. & Louër, D. (1991). J. Appl. Cryst. 24, 987-993.  [CrossRef] [ChemPort] [details]
Brese, N. E. & O'Keeffe, M. (1991). Acta Cryst. B47, 192-197.  [CrossRef] [details]
Brixner, L. H., Calabrese, J. C. & Chen, H.-Y. (1985). J. Less-Common Met. 110, 397-410.  [CrossRef] [ChemPort]
Brown, I. D. (1981). Structure and Bonding in Crystals, Vol. 2, edited by M. O'Keefe & A. Navrotsky, pp. 1-30. New York: Academic Press.
Brown, I. D. (1992). Z. Kristallogr. 199, 255-272.  [ChemPort]
Dowty, E. (2000). ATOMS for Windows. Shape Software, Kingsport, Tennessee, USA.
Fei, Z., Peimin, G., Guobao, L., Fuhui, L., Shujian, T. & Xiping, J. (2003). Mater. Res. Bull. 38, 931-940.
Minami, T., Kobayashi, Y., Miyata, T. & Yamazaki, M. (2003). Thin Solid Films, 425, 35-40.  [CrossRef] [ChemPort]
Minami, T., Miyata, T., Ueno, T. & Urano, Y. (2002). US Patent No. 2002/0047515 Al.
Minami, T., Miyata, T., Ueno, T. & Urano, Y. (2004). US Patent No. 6707249 B2.
Minami, T., Yamazaki, M., Miyata, T. & Shirai, T. (2001). Jpn J. Appl. Phys. 40, L864-L866.  [CrossRef] [ChemPort]
Natori, E., Kijima, T., Furuyama, K. & Tasaki, Y. (2004). Eur. Patent No. EP20020738688.
Redhammer, G. J., Roth, G. & Amthauer, G. (2007). Acta Cryst. C63, i93-i95.  [CrossRef] [details]
Rodríguez-Carvajal, J. (2006). FULLPROF. URL: http://www.ill.eu/sites/fullprof/ php/reference.html.
Siemens (1993). DIFFRAC/AT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.
Thompson, P., Cox, D. E. & Hastings, J. B. (1987). J. Appl. Cryst. 20, 79-83.  [CrossRef] [ChemPort] [details]
Zhao, F., Guo, P., Li, G., Liao, F., Tian, S. & Jing, X. (2003). Mater. Res. Bull. 38, 931-940.  [CrossRef] [ChemPort]

Acta Cryst (2009). E65, i60  [ doi:10.1107/S1600536809026579 ]

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