Campus Units

Chemistry

Document Type

Article

Publication Version

Published Version

Publication Date

2013

Journal or Book Title

Journal of the American Chemical Society

Volume

135

First Page

11023

Last Page

11031

DOI

10.1021/ja401378q

Abstract

Au-rich polar intermetallics exhibit a wide variety of structural motifs, and this hexagonal-diamond-like gold host is unprecedented. The series Ba2Au6(Au,T)3 (T = Zn, Cd, Ga, In, or Sn), synthesized through fusion of the elements at 700–800 °C followed by annealing at 400–500 °C, occur in space group Rc (a ≈ 8.6–8.9 Å, c ≈ 21.9–22.6 Å, and Z = 6). Their remarkable structure, generated by just three independent atoms, features a hexagonal-diamond-like gold superstructure in which tunnels along the 3-fold axes are systematically filled by interstitial Ba atoms (blue) and triangles of disordered (Au,T)3 atoms (green) in 2:1 proportions. The Au/Zn mixing in the latter spans ∼34 to 87% Zn, whereas the Au/Sn result is virtually invariant compositionally. Complementary bonding between the gold lattice and the disordered (Au,T)3 units is substantial and very regular. Bonding and charge density analyses indicate delocalized bonding within the gold host and the (Au,T)3 triangular units, and moderately polarized bonding between Ba and the electronegative framework. The new structure can also be viewed empirically as the result of an atom-by-triad [i.e., Ba by (Au,T)3 triangle] topological substitution in a BaAu2 (AlB2-type) superstructure.

Comments

This is an article from the Journal of the American Chemical Society 135 (2013): 11023, doi: 10.1021/ja401378q. Posted with permission.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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