Campus Units

Chemistry, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

2011

Journal or Book Title

Inorganic Chemistry

Volume

50

Issue

21

First Page

11091

Last Page

11098

DOI

10.1021/ic2016275

Abstract

The phase regions around quasicrystals and approximants (QC/ACs) are rich pools for electron-poor intermetallics with novel, complex structures, and bonding patterns. The present SrAu4.30(1)In1.70(1) (1) and CaAg3.54(1)In1.88(1) (2) were synthesized through chemical tunings of the model CaAu4In2 (YCd6-Type) AC. Single crystal X-ray diffraction analyses reveals that crystal 1 has Pnma (CeCu6-type) symmetry, with a = 9.102(1) Å, b = 5.6379(9) Å, and c = 11.515(2) Å. The building block in 1 is a 19-vertex cluster Sr@Au9In4M6 (M = Au/In), which vividly mimics Ca@(Au,In)18 in Ca3Au12.4In6.1 (YCd6-type) in geometry. These clusters aggregate into one-dimensional columns extending along the b axis. Crystal 2 (P6/mmm, a = 20.660(3) Å, c = 9.410(2) Å) is closely related to Na26Cd141 (hP167) and Y13Pd40Sn31 (hP168), which are differentiated by the selective occupation of Wyckoff 1a (0 0 0) or 2d (1/3 2/3 1/2) sites by Cd or Pd. Crystal 2 adopts the Na26Cd141 structure, but the 1a site is split into two partially occupied sites. The synergistic disorder in the hexagonal tunnels along c is a major property. The valence electron count per atom (e/a) values for 1 and 2 are 1.63 and 1.74, respectively, the lowest among any other ternary phases in each system. These values are close to those of ACs in the Ca–Au–M (M = Ga, In) systems. Electronic structures for both are discussed in terms of the results of TB-LMTO-ASA calculations.

Comments

This is an article from Inorganic Chemistry 50 (2011): 11091, doi: 10.1021/ic2016275. Posted with permission.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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