Skip to main content
Open Access Publications from the University of California

On the structure and stability of BaAl4-type ordered derivatives in the Sr-Au-Sn system for the 600 ° C section

  • Author(s): Lin, Q
  • Zhang, Y
  • Taufour, V
  • Lamichhane, TN
  • Bud'Ko, SL
  • Canfield, PC
  • Dennis, K
  • Miller, G
  • et al.

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. The well-known BaAl4-type structure consists of three ordered ternary derivatives, i.e., BaNiSn3-(I4mm), ThCr2Si2-(I4/mmm), and CaBe2Ge2-type (P4/nmm). Few systems, such as Ba-Au-Sn, have been confirmed to manifest all three types as a function of valence electron count. In this work, the SrAuxSn4-xsolid solution at the 600 ° C section was studied thoroughly using both single crystal and powder X-ray diffraction. The crystal structures and phase width for the CaBe2Ge2-type SrAuxSn4-xsolid solution were established to be α = 4.6528(2)-4.6233(3) Å and c = 11.3753(4)-11.2945(10) Å for x ≈ 1.65(1)-2.19(1). In the structure of SrAu2Sn2, no Au/Sn mixing was found, but for x < 2 compositions, Au/Sn mixings were only located at the Wyckoff 2α (3/4 1/4 0) site and for x > 2 compositions, at the 2b (3/4 1/4 1/2) site. Differential scanning calorimetry (DSC) analyses indicated that no phase transition occurred for the CaBe2Ge2-type SrAuxSn4-xphase up to 950 ° C. Attempts to synthesize the ThCr2Si2-and BaNiSn3-type SrAuxSn4-xphases under the same reaction conditions were unsuccessful, and the BaNiSn3-type phase could not be attained even at a pressure of 3 GPa. The instability of a BaNiSn3-type "SrAuSn3" was investigated by both DSC measurements and first principles electronic structure calculations.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View