Received 18 November 2011
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: email@example.com
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.
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).
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 ).
Financial support from the Ministry of Education and Science, Youth and Sport of Ukraine (No. 0111U001089) is gratefully acknowledged.
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