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'Pd20Sn13' revisited: crystal structure of Pd6.69Sn4.31.

Klein W, Jin H, Hlukhyy V, Fässler TF - Acta Crystallogr E Crystallogr Commun (2015)

Bottom Line: The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids.One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3):0.62 (3).One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b).

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Affiliation: Technische Universität München, Department of Chemistry, Lichtenbergstrasse 4, 85747 Garching, Germany.

ABSTRACT
The crystal structure of the title compound was previously reported with composition 'Pd20Sn13' [Sarah et al. (1981 ▸). Z. Metallkd, 72, 517-520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6 were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtained via a solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3):0.62 (3). One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b).

No MeSH data available.


The crystal structure of Pd6.69Sn4.31, emphasizing the relationship to the AlB2 structure type. The ‘Al n’ layers represent planes which are occupied by Al atoms in AlB2, the ‘B n’ layers those with B atoms, respectively. Anisotropic displacement ellipsoids are drawn at the 90% probability level.
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fig1: The crystal structure of Pd6.69Sn4.31, emphasizing the relationship to the AlB2 structure type. The ‘Al n’ layers represent planes which are occupied by Al atoms in AlB2, the ‘B n’ layers those with B atoms, respectively. Anisotropic displacement ellipsoids are drawn at the 90% probability level.

Mentions: The crystal structure of the title compound can be described as a defect variant of the AlB2 structure type, where 1/8 of the boron atoms are missing. The symmetry reduction from P6/mmm to P3221 with respect to AlB2 results in 13 different crystallographic positions for the Pd and Sn atoms instead of only two, and a more complicated stacking of atomic planes including six differently packed layers for each of the former two, as shown in Fig. 1 ▸. The remaining atomic sites of the B atoms in AlB2 are now substituted by seven independent atoms (Pd6, Pd7, Pd8, Sn2, Sn3, Sn4, and Sn5), the ‘Al’ layers are substituted alternatingly by Sn1, Pd3, Pd5, (layers ‘Al1’, ‘Al3’, ‘Al5’ in Fig. 1 ▸), and by Pd1, Pd2, and Pd4 (‘Al2’, ‘Al4’, ‘Al6’), respectively.


'Pd20Sn13' revisited: crystal structure of Pd6.69Sn4.31.

Klein W, Jin H, Hlukhyy V, Fässler TF - Acta Crystallogr E Crystallogr Commun (2015)

The crystal structure of Pd6.69Sn4.31, emphasizing the relationship to the AlB2 structure type. The ‘Al n’ layers represent planes which are occupied by Al atoms in AlB2, the ‘B n’ layers those with B atoms, respectively. Anisotropic displacement ellipsoids are drawn at the 90% probability level.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4518917&req=5

fig1: The crystal structure of Pd6.69Sn4.31, emphasizing the relationship to the AlB2 structure type. The ‘Al n’ layers represent planes which are occupied by Al atoms in AlB2, the ‘B n’ layers those with B atoms, respectively. Anisotropic displacement ellipsoids are drawn at the 90% probability level.
Mentions: The crystal structure of the title compound can be described as a defect variant of the AlB2 structure type, where 1/8 of the boron atoms are missing. The symmetry reduction from P6/mmm to P3221 with respect to AlB2 results in 13 different crystallographic positions for the Pd and Sn atoms instead of only two, and a more complicated stacking of atomic planes including six differently packed layers for each of the former two, as shown in Fig. 1 ▸. The remaining atomic sites of the B atoms in AlB2 are now substituted by seven independent atoms (Pd6, Pd7, Pd8, Sn2, Sn3, Sn4, and Sn5), the ‘Al’ layers are substituted alternatingly by Sn1, Pd3, Pd5, (layers ‘Al1’, ‘Al3’, ‘Al5’ in Fig. 1 ▸), and by Pd1, Pd2, and Pd4 (‘Al2’, ‘Al4’, ‘Al6’), respectively.

Bottom Line: The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids.One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3):0.62 (3).One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b).

View Article: PubMed Central - HTML - PubMed

Affiliation: Technische Universität München, Department of Chemistry, Lichtenbergstrasse 4, 85747 Garching, Germany.

ABSTRACT
The crystal structure of the title compound was previously reported with composition 'Pd20Sn13' [Sarah et al. (1981 ▸). Z. Metallkd, 72, 517-520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6 were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtained via a solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3):0.62 (3). One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b).

No MeSH data available.