The pyrochlore-type molybdate Pr2Mo1.73Sc0.27O7

Gall, P.; Gougeon, P.

doi:10.1107/S1600536812045138

Volume 68
Part 12
Page i92
December 2012

Received 19 October 2012
Accepted 31 October 2012
Online 10 November 2012

Key indicators
Single-crystal X-ray study
T = 293 K
Mean (Pr-O) = 0.001 Å
Disorder in main residue
R = 0.018
wR = 0.047
Data-to-parameter ratio = 25.1
Details

The pyrochlore-type molybdate Pr₂Mo_1.73Sc_0.27O₇

Philippe Gall ^a and Patrick Gougeon ^a ^*

^aUnité Sciences Chimiques de Rennes, UMR CNRS No. 6226, Université de Rennes I - INSA Rennes, Campus de Beaulieu, 35042 Rennes CEDEX, France
Correspondence e-mail: Patrick.Gougeon@univ-rennes1.fr

Dipraseodymium molybdenum scandium heptaoxide, Pr₂Mo_1.73Sc_0.27O₇, crystallizes in the cubic pyrochlore-type structure. In the crystal, (Mo,Sc)O₆ octahedra are linked together by common corners, forming a three-dimensional [(Mo,Sc)₂O₆] framework. The Pr atom and another O atom atom are located in the voids of this framework. The Mo and the Sc atom are distributed statistically over the same 16d crystallographic position, with site-occupancy factors of 0.867 (3) and 0.133 (3), respectively. The Pr³⁺ ions are surrounded by six O atoms from the MoO₆ octahedra and by two other O atoms, forming a ditrigonal scalenohedron. All atoms lie on special positions. The Pr and the statistically distributed (Mo,Sc) sites are in the 16c and 16d positions with .-3m symmetry, and two O atoms are in 48f and 8a positions with 2.mm and -43m site symmetry, respectively.

Related literature

For pyrochlore-type molybdates, see, for example: Hubert (1974); Subramanian et al. (1983); Gall & Gougeon (2008). For the physical properties of some rare-earth molybdate pyrochlores, see: Hill et al. (1989); Ali et al. (1989); Miyoshi et al. (2001, 2003). An attempt to synthesize ScPr₉Mo₁₆O₃₅, a compound with the LiNd₉Mo₁₆O₃₅ type structure (Gougeon et al., 2011), was unsuccessful, resulting in a multiphase product with Pr₂Mo_1.73Sc_0.27O₇ and Pr₁₆Mo₂₁O₅₆ (Gougeon & Gall, 2011) as predominant phases.

Experimental

Crystal data

Pr₂Mo_1.73Sc_0.27O₇
M_r = 571.69
Cubic, $[F d \overline 3m ]$
a = 10.5271 (3) Å
V = 1166.61 (6) Å³
Z = 8
Mo K radiation
= 20.33 mm^-1
T = 293 K
0.10 × 0.06 × 0.05 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: analytical (de Meulenaar & Tompa, 1965) T_min = 0.302, T_max = 0.461
9208 measured reflections
326 independent reflections
269 reflections with I > 2(I)
R_int = 0.044

Refinement

R[F² > 2(F²)] = 0.018
wR(F²) = 0.047
S = 1.33
326 reflections
13 parameters
_max = 0.79 e Å^-3
_min = -0.81 e Å^-3

Table 1
Selected bond lengths (Å)

Pr1-O2	2.2792
Pr1-O1ⁱ	2.5795 (13)
Mo1-O1ⁱⁱ	2.0440 (8)
Symmetry codes: (i) $[z-{\script{1\over 4}}, x-{\script{1\over 4}}, -y]$ ; (ii) $[x, y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: COLLECT (Nonius, 1998); cell refinement: COLLECT; data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXL97.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RU2045 ).

Acknowledgements

Intensity data were collected at the Centre de diffractométrie de l'Université de Rennes I (www.cdifx.univ-rennes1.fr).

References

Ali, N., Hill, M., Labroo, S. & Greedan, J. (1989). J. Solid State Chem. 83, 178-187.
Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.
Brandenburg, K. (2001). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Duisenberg, A. J. M., Kroon-Batenburg, L. M. J. & Schreurs, A. M. M. (2003). J. Appl. Cryst. 36, 220-229.
Gall, P. & Gougeon, P. (2008). Acta Cryst. E64, i42.
Gougeon, P. & Gall, P. (2011). Acta Cryst. E67, i34-i35.
Gougeon, P., Gall, P., Cuny, J., Gautier, R., Le Polles, L., Delevoye, L. & Trebosc, J. (2011). Chem. Eur. J. 17, 13806-130813.
Hill, P., Labroo, S., Zhang, X. & Ali, N. (1989). J. Less Common Met. 149, 327-330.
Hubert, Ph. H. (1974). Bull. Soc. Chim. Fr. 11, 2385-2386.
Meulenaer, J. de & Tompa, H. (1965). Acta Cryst. A19, 1014-1018.
Miyoshi, K., Honda, K., Hiraoka, T., Fujiwara, K., Takeuchi, J. & Hamasaki, T. (2003). Physica B, 329, 1059-1060.
Miyoshi, K., Honda, K., Yamashita, T., Fujiwara, K. & Takeuchi, J. (2001). J. Magn. Magn. Mater. 226, 898-899.
Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Subramanian, M. A., Aravamudan, G. & Subba Rao, G. V. (1983). Prog. Solid State Chem. 15, 55-143.

inorganic compounds