Redetermination of LaZn5 based on single crystal X-ray diffraction data

Oshchapovsky, I.; Zelinska, O.; Rozdzynska-Kielbik, B.; Pavlyuk, V.

doi:10.1107/S1600536811050987

Volume 68
Part 1
Page i1
January 2012

Received 18 November 2011
Accepted 27 November 2011
Online 3 December 2011

Key indicators
Single-crystal X-ray study
T = 296 K
Mean (La-Zn) = 0.001 Å
R = 0.018
wR = 0.037
Data-to-parameter ratio = 8.1
Details

Redetermination of LaZn₅ based on single crystal X-ray diffraction data

Igor Oshchapovsky,^a ^* Oksana Zelinska,^a Beata Rozdzynska-Kielbik ^b and Volodymyr Pavlyuk ^a,^b

^aDepartment of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryla i Mefodia str. 6, 79005 Lviv, Ukraine, and ^bInstitute of Chemistry, Environmental Protection and Biotechnology, Jan Dlugosz University, Armii Krajowej Ave. 13/15, 42-200 Czestochowa, Poland
Correspondence e-mail: romaniuk@ua.fm

The crystal structure of the already known binary title compound LaZn₅ (lanthanum pentazinc) (space group P6/mmm, Pearson symbol hP6, CaCu₅ structure type) has been redetermined from single-crystal X-ray diffraction data. In contrast to previous determinations based on X-ray powder data [Nowotny (1942). Z. Metallkd. 34, 247-253; de Negri et al. (2008). Intermetallics, 16, 168-178], where unit-cell parameters and assignment of the structure type were reported, the present study reveals anisotropic displacement parameters for all atoms. The crystal structure consists of three crytallographically distinct atoms. The La atom (Wyckoff site 1a, site symmetry 6/mmm) is surrounded by 18 Zn atoms and two La atoms. The coordination polyhedron around one of the Zn atoms (Wyckoff site 2c, site symmetry -6m2) is an icosahedron made up from three La and nine Zn atoms. The other Zn atom (Wyckoff site 3g, site symmetry mmm) is surrounded by four La and eight Zn atoms. Bonding between atoms is explored by means of the TB-LMTO-ASA (tight-binding linear muffin-tin orbital atomic spheres approximation) program package. The positive charge density is localized around La atoms, and the negative charge density is around Zn atoms, with weak covalent bonding between the latter.

Related literature

For previous structural studies of the title compound, see: de Negri et al. (2008); Nowotny (1942). For general background, see: Andersen et al. (1986); Berche et al. (2009); Oshchapovsky et al. (2011a,b); Pavlyuk et al. (2009); Zelinska et al. (2004).

Experimental

Crystal data

LaZn₅
M_r = 465.86
Hexagonal, P 6/m m m
a = 5.4654 (17) Å
c = 4.2574 (15) Å
V = 110.13 (6) Å³
Z = 1
Mo K radiation
= 36.05 mm^-1
T = 296 K
0.04 × 0.02 × 0.02 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004) T_min = 0.410, T_max = 0.478
1123 measured reflections
73 independent reflections
62 reflections with I > 2(I)
R_int = 0.069

Refinement

R[F² > 2(F²)] = 0.018
wR(F²) = 0.037
S = 1.17
73 reflections
9 parameters
_max = 1.11 e Å^-3
_min = -0.71 e Å^-3

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006) and VESTA (Momma & Izumi, 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2565 ).

Acknowledgements

Financial support from the Ministry of Education and Science, Youth and Sport of Ukraine (No. 0111U001089) is gratefully acknowledged.

References

Andersen, K., Povlovska, Z. & Jepsen, O. (1986). Phys. Rev. B, 34, 51-53.
Berche, A., Record, M.-C. & Rogez, J. (2009). Open Thermodynam. J. 3, 7-16.
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Bruker (2004). SADABS, APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Momma, K. & Izumi, F. (2008). J. Appl. Cryst. 41, 653-658.
Negri, S. de, Solokha, P., Saccone, A. & Pavlyuk, V. (2008). Intermetallics, 16, 168-178.
Nowotny, H. (1942). Z. Metallkd. 34, 247-253.
Oshchapovsky, I., Pavlyuk, V., Dmytriv, G., Chumak, I. & Ehrenberg, H. (2011b). Acta Cryst. E67, i65.
Oshchapovsky, I., Pavlyuk, V., Dmytriv, G. & White, F. (2011a). Acta Cryst. E67, i43.
Pavlyuk, V., Oshchapovsky, I. & Marciniak, B. (2009). J. Alloys Compd, 477, 145-148.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.
Zelinska, O., Conrad, M. & Harbrecht, B. (2004). Z. Kristallogr. New Cryst. Struct. 219, 357-358.

inorganic compounds