Campus Units

Ames Laboratory, Chemistry

Document Type

Article

Publication Version

Published Version

Publication Date

2003

Journal or Book Title

Journal of the American Chemical Society

Volume

125

Issue

49

First Page

15183

Last Page

15190

DOI

10.1021/ja037649z

Abstract

X-ray single crystal and powder diffraction studies on the Gd5GaxGe4-x system with 0 ≤ x ≤ 2.2 reveal dependence of interslab T−T dimer distances and crystal structures themselves on valence electron concentration (T is a mixture of Ga and Ge atoms). While the Gd5GaxGe4-x phases with 0 ≤ x ≤ 0.6 and valence electron concentration of 30.4−31 e-/formula crystallize with the Sm5Ge4-type structure, in which all interslab T−T dimers are broken (distances exceeding 3.4 Å), the phases with 1 ≤ x ≤ 2.2 and valence electron concentration of 28.8−30 e-/formula adopt the Pu5Rh4- or Gd5Si4-type structures with TT dimers between the slabs. An orthorhombic Pu5Rh4-type structure, which is intermediate between the Gd5Si4- and Sm5Ge4-type structures, has been identified for the Gd5GaGe3 composition. Tight-binding linear-muffin-tin-orbital calculations show that substitution of three-valent Ga by four-valent Ge leads to larger population of the antibonding states within the dimers and, thus, to dimer stretching and eventually to dimer cleavage.

Comments

Reprinted (adapted) with permission from J. Am. Chem. Soc., 2003, 125 (49), pp 15183–15190. Copyright 2003 American Chemical Society.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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