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Synthesis, structure, and bonding of Sc4MgxCu 15 - xGa∼7.5 (x = 0, 0.5). Two incommensurately modulated scandium substitution derivatives of cubic Mg 2Cu6Ga5

Lin, Qisheng ; Lidin, Sven LU and Corbett, John D. (2008) In Inorganic Chemistry 47(3). p.1020-1029
Abstract

The substitution of scandium for magnesium in Mg2Cu 6Ga5 (Mg2Zn11-type) yields an irrational superstructure phase that includes the refined compositions, Sc 4Mg0.50(2)Cu14.50(2)Ga7.61(2) and Sc4Cu14.76(2)Ga7.51(2). These crystallize in Cmmm, a = ∼8.31 Å, b = ∼21.72 Å, c = ∼8.30 Å. The structures feature Sc2 dimers, Cu6 octahedra, a 3D CuGa (Cu12Ga2) framework, and arachno gallium-centered Cu 4Ga6 icosahedra that are condensed into zigzag chains. The arrangement of these building blocks exhibits a topologic relationship to... (More)

The substitution of scandium for magnesium in Mg2Cu 6Ga5 (Mg2Zn11-type) yields an irrational superstructure phase that includes the refined compositions, Sc 4Mg0.50(2)Cu14.50(2)Ga7.61(2) and Sc4Cu14.76(2)Ga7.51(2). These crystallize in Cmmm, a = ∼8.31 Å, b = ∼21.72 Å, c = ∼8.30 Å. The structures feature Sc2 dimers, Cu6 octahedra, a 3D CuGa (Cu12Ga2) framework, and arachno gallium-centered Cu 4Ga6 icosahedra that are condensed into zigzag chains. The arrangement of these building blocks exhibits a topologic relationship to Mg2Cu6Ga5. Further studies reveal that the quaternary compound exhibits incommensurate modulations along a, with q = (0.694, 0, 0). Structure refinements with superspace group Xmmm(a00)000 led to saw-tooth modulations for two fractional or mixed sites that avoid short Cu-Ga distances. Band structure analyses reveal that the Fermi surface and bonding are sensitive to the incommensurately modulated atoms.

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author
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type
Contribution to journal
publication status
published
in
Inorganic Chemistry
volume
47
issue
3
pages
10 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:39749105998
ISSN
0020-1669
DOI
10.1021/ic701853c
language
English
LU publication?
no
id
16293a99-6d87-4677-b6c8-a67064bf971b
date added to LUP
2019-04-08 15:13:04
date last changed
2025-10-14 13:01:37
@article{16293a99-6d87-4677-b6c8-a67064bf971b,
  abstract     = {{<p>The substitution of scandium for magnesium in Mg<sub>2</sub>Cu <sub>6</sub>Ga<sub>5</sub> (Mg<sub>2</sub>Zn<sub>11</sub>-type) yields an irrational superstructure phase that includes the refined compositions, Sc <sub>4</sub>Mg<sub>0.50(2)</sub>Cu<sub>14.50(2)</sub>Ga<sub>7.61(2)</sub> and Sc<sub>4</sub>Cu<sub>14.76(2)</sub>Ga<sub>7.51(2)</sub>. These crystallize in Cmmm, a = ∼8.31 Å, b = ∼21.72 Å, c = ∼8.30 Å. The structures feature Sc<sub>2</sub> dimers, Cu<sub>6</sub> octahedra, a 3D CuGa (Cu<sub>12</sub>Ga<sub>2</sub>) framework, and arachno gallium-centered Cu <sub>4</sub>Ga<sub>6</sub> icosahedra that are condensed into zigzag chains. The arrangement of these building blocks exhibits a topologic relationship to Mg<sub>2</sub>Cu<sub>6</sub>Ga<sub>5</sub>. Further studies reveal that the quaternary compound exhibits incommensurate modulations along a, with q = (0.694, 0, 0). Structure refinements with superspace group Xmmm(a00)000 led to saw-tooth modulations for two fractional or mixed sites that avoid short Cu-Ga distances. Band structure analyses reveal that the Fermi surface and bonding are sensitive to the incommensurately modulated atoms.</p>}},
  author       = {{Lin, Qisheng and Lidin, Sven and Corbett, John D.}},
  issn         = {{0020-1669}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{3}},
  pages        = {{1020--1029}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Inorganic Chemistry}},
  title        = {{Synthesis, structure, and bonding of Sc<sub>4</sub>Mg<sub>x</sub>Cu <sub>15</sub> - <sub>x</sub>Ga<sub>∼7.5</sub> (x = 0, 0.5). Two incommensurately modulated scandium substitution derivatives of cubic Mg <sub>2</sub>Cu<sub>6</sub>Ga<sub>5</sub>}},
  url          = {{http://dx.doi.org/10.1021/ic701853c}},
  doi          = {{10.1021/ic701853c}},
  volume       = {{47}},
  year         = {{2008}},
}