Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-26T16:38:03.108Z Has data issue: false hasContentIssue false
  • English
  • Français

Crystal structure of lanthanum oxyorthosilicate, La2SiO5

Published online by Cambridge University Press:  01 March 2012

Koichiro Fukuda ,
Tomoyuki Iwata  and
Eric Champion
Koichiro Fukuda
Affiliation:
Department of Environmental and Materials Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
Tomoyuki Iwata
Affiliation:
Department of Environmental and Materials Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
Eric Champion
Affiliation:
Science des Procédés Céramiques et de Traitements de Surface, Université de Limoges, UMR CNRS 6638, 123 Avenue Albert Thomas, 87060 Limoges Cedex, France
Get access Rights & Permissions [Opens in a new window]

Abstract

The crystal structure of La2SiO5 was refined from laboratory X-ray powder diffraction data (CuKα1) using the Rietveld method. The crystal structure is monoclinic (space group P21∕c,Z=4) with lattice dimensions a=0.93320(2) nm, b=0.75088(1) nm, c=0.70332(1) nm, β=108.679(1)°, and V=0.46687(1) nm3. The final reliability indices were Rwp=7.14%, RP=5.52%, and RB=3.83%. There are two La sites in the structural model, La1 and La2. La1 is ninefold coordinated to oxygen, forming a tricapped trigonal prism with a mean La1-O distance of 0.263 nm. The La2O7 coordination polyhedron is a distorted capped octahedron with a mean La2-O distance of 0.251 nm. The La1O9 polyhedra share faces and the La2O7 polyhedra share edges, forming two sets of sheets that alternate parallel to the (100) plane. These sheets are linked through SiO4 tetrahedra and non-silicon-bonded oxygen atoms to form a three-dimensional structure. This compound is isomorphous with the low-temperature (X1) phases of R2SiO5 (R=Y and Gd). The volumes of RO9 polyhedra steadily increase with increasing ionic radius of R, from Y3+ to Gd3+ to La3+, which causes substantial volumetric expansion of the crystals.

Keywords

lanthanum oxyorthosilicatecrystal structurepowder diffractionRietveld refinement
Type
Technical Articles
Information
Powder Diffraction , Volume 21 , Issue 4 , December 2006 , pp. 300 - 303
Copyright
Copyright © Cambridge University Press 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Baur, W. H. (1971). “Prediction of bond length variations in silicon-oxygen bonds,” Am. Mineral. AMMIAY 56, 1573–1599.Google Scholar
Brese, N. E. and O’Keeffe, M. (1991). “Bond-valence parameters for solids,” Acta Crystallogr. ASBSDK 10.1107/S0108768190011041 47, 192–197.CrossRefGoogle Scholar
Brown, I. D. and Altermatt, D. (1985). “Bond-valence parameters obtained from a systematic analysis of the inorganic crystal structure database,” Acta Crystallogr. ASBSDK 10.1107/S0108768185002063 41, 244–247.CrossRefGoogle Scholar
Dong, C. (1999). “Windows-95-based program for powder X-ray diffraction data processing,” J. Appl. Crystallogr. JACGAR 10.1107/S0021889899003039 32, 838.CrossRefGoogle Scholar
Felsche, J. (1973). “The crystal chemistry of the rare-earth silicates” in Structure and Bonding, edited by Dunitz, J. D., Hemmerich, P., Ibers, J. A., Jorgensen, C. K., Neilands, J. B., Nyholm, Sir R. S., Reinen, D., Williams, R. J. P. (Springer-Verlag, Berlin), Vol. 13, pp. 99–197.Google Scholar
Ferid, M. and Horchani-Naifer, K. (2004). “Synthesis, crystal structure and vibrational spectra of a new form of diphosphate NaLaP2O7,” Mater. Res. Bull. MRBUAC 39, 2209–2217.CrossRefGoogle Scholar
Fukuda, K. and Matsubara, H. (2003). “Anisotropic thermal expansion in yttrium silicate,” J. Mater. Res. JMREEE 18, 1715–1722.CrossRefGoogle Scholar
Izumi, F. and Dilanian, R. A. (2002). “Structure refinement based on the maximum-entropy method from powder diffraction data” in Recent Research Developments in Physics, (Transworld Research Network, Trivandrum, India), Vol. 3, Part II, pp. 699–726.Google Scholar
Izumi, F., and Ikeda, T. (2000). “A Rietveld-analysis program RIETAN-98 and its applications to zeolites,” Mater. Sci. Forum MSFOEP 321–324, 198–203.CrossRefGoogle Scholar
Leonyuk, N. I., Belokoneva, E. L., Bocelli, G., Right, L., Shvanskii, E. V., Henrykhson, R. V., Kulman, N. V., and Kozhbakhteeva, D. E. (1999). “Crystal growth and structural refinements of the Y2SiO5, Y2SiO7 and LaBSiO5 single crystals,” Cryst. Res. Technol. CRTEDF 10.1002/(SICI)1521-4079(199911)34:9<1175::AID-CRAT1175>3.0.CO;2-2 34, 1175–1182.3.0.CO;2-2>CrossRefGoogle Scholar
Makovicky, E., and Balic-Zunic, T. (1998). “New measure of distortion for coordination polyhedra,” Acta Crystallogr. ASBSDK 10.1107/S0108768198003905 54, 766–773.CrossRefGoogle Scholar
Maksimov, B. A., Kharitonov, Y. A., Ilyukhin, V. V., and Belov, N. V. (1968). “Crystal structure of yttrium oxysilicate,” Dokl. Akad. Nauk SSSR DANKAS 183, 1072–1075.Google Scholar
Maksimov, B. A., Ilyukhin, V. V., Kharitonov, Y. A., and Belov, N. V. (1970). “Crystal structure of yttrium oxyorthosilicate Y2O3∙SiO2=Y2SiO5,” Kristallografiya KRISAJ 15, 926–933.Google Scholar
Pawley, G. S. (1981). “Unit-cell refinement from powder diffraction scans,” J. Appl. Crystallogr. JACGAR 10.1107/S0021889881009618 14, 357–361.CrossRefGoogle Scholar
Ralle, M. and Jansen, M. (1994). “Preparation and crystal structure of new lanthanum aurates La4Au2O9,” J. Alloys Compd. JALCEU 203, 7–13.CrossRefGoogle Scholar
Shannon, R. D. (1976). “Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides,” Acta Crystallogr. ACACBN 10.1107/S0567739476001551 32, 751–767.CrossRefGoogle Scholar
Smith, G. S. and Snyder, R. L. (1979). “F N: A criterion for rating powder diffraction patterns and evaluating the reliability of powder-pattern indexing,” J. Appl. Crystallogr. JACGAR 10.1107/S002188987901178X 12, 60–65.CrossRefGoogle Scholar
Smolin, Y. I. and Tkachev, S. P. (1969). “Determination of the structure of gadolinium orthosilicate Gd2O3∙SiO2,” Kristallografiya KRISAJ 14, 22–25.Google Scholar
Toraya, H. (1986). “Whole-powder-pattern fitting without reference to a structural model: application to X-ray powder diffractometer data,” J. Appl. Crystallogr. JACGAR 10.1107/S0021889886088982 19, 440–447.CrossRefGoogle Scholar
Toraya, H. (1990). “Array-type universal profile function for powder pattern fitting,” J. Appl. Crystallogr. JACGAR 10.1107/S002188989000704X 23, 485–491.CrossRefGoogle Scholar
Wang, J., Tian, S., Li, G., Liao, F., and Jing, X. (2001). “Preparation and X-ray characterization of low-temperature phases of R2SiO5 (R=Rare Earth Elements),” Mater. Res. Bull. MRBUAC 10.1016/S0025-5408(01)00664-X 36, 1855–1861.CrossRefGoogle Scholar
Werner, P.-E., Eriksson, L., and Westdahl, M. (1985). “TREOR, a semi-exhaustive trial-and-error powder indexing program for all symmetries,” J. Appl. Crystallogr. JACGAR 10.1107/S0021889885010512 18, 367–370.CrossRefGoogle Scholar
de Wolff, P. M. (1968). “A simplified criterion for the reliability of a powder pattern indexing,” J. Appl. Crystallogr. JACGAR 10.1107/S002188986800508X 1, 108–113.CrossRefGoogle Scholar
Young, R. A. (1993). “Introduction to the Rietveld method,” in The Rietveld Method, edited by Young, R. A. (Oxford U.P., Oxford), pp. 1–38.CrossRefGoogle Scholar