R14(Au, M)51 (R = Y, La–Nd, Sm–Tb, Ho, Er, Yb, Lu; M = Al, Ga, Ge, In, Sn, Sb, Bi): Stability Ranges and Site Preference in the Gd14Ag51 Structure Type
journal contributionposted on 19.12.2017, 00:00 by Chris Celania, Volodymyr Smetana, Alessia Provino, Pietro Manfrinetti, Anja-Verena Mudring
Twenty new ternary representatives of the Gd14Ag51 structure type have been synthesized within the R-Au-M family (R = Y, La–Nd, Sm–Tb, Ho, Er, Yb, Lu; M = Al, Ga, Ge, In, Sn, Sb, Bi) using solid state synthesis techniques. The list of post transition metals (M) involved in the formation of this type of structure could be augmented by five new representatives. All compounds crystallize in the hexagonal space group P6/m (#175) with the unit cell ranges of a = 12.3136(2)–12.918(1) Å and c = 8.9967(3)–9.385(1) Å, and incorporate different degrees of Au/M mixing. The involvement of the post transition element in the structure varies from one to another compound both qualitatively and quantitatively. A rather significant phase width can be expected for the majority of compounds, however, not without exclusions. The distribution of the post transition metals within the structure has been analyzed via single crystal X-ray diffraction. While the positional disorder of one near-origin Au position is expectable for all compounds due to steric reasons, two specimens show an obvious deviation from the others including another Au position split along the c axis. Possible factors affecting this behavior are discussed.
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specimens showPossible factorspost transition elementBicompoundR-Au-M familyGeGaunit cell rangessteric reasonsHophase widthpost transition metalsR 14ErGd 14 Ag 51 structure typeposition splitcrystal X-ray diffractionc axisSmSbstate synthesis techniquesternary representativesGd 14 Ag 51 Structure TypeLaAlLuYbSite PreferenceSn