Structure-Composition Subtleties in NaZn13-type Derivatives of Sr/Ca(AuxAl1–x)12–13
- Iowa State Univ., Ames, IA (United States)
- Iowa State Univ., Ames, IA (United States); Ames Lab., Ames, IA (United States)
In the ternary (Sr/Ca)-Au-Al phase space for 5–8 at % Sr/Ca and nearly equimolar mixture of Au and Al, five new NaZn13-derivatives Sr/Ca(AuxAl1–x)12–13 were discovered and their atomic site preferences and electronic structures were studied: (1) at higher Au content, cubic SrAuxAl13–x [7.24(2) ≥ x ≥ 6.68(2)] shows no obvious atomic site preferences; (2) at lower Au content, tetragonal SrAuxAl13–x [6.59(1) ≥ x ≥ 6.35(3)] shows icosahedra exclusively centered by Al and preferential atomic arrangements to maximize the number of Au–Al (or Al-rich) shortest distances; (3) a monoclinic SrAu6.10(3)Al6.40 compound was uncovered from studies of a single crystal specimen with problematic refinement issues but more detailed powder X-ray diffraction analysis which suggest even more pronounced geometric distortion from the NaZn13-type structure as well as preferential arrangements for Au–Al nearest contacts; (4) tetragonal SrAu5.75(2)Al6.25 with all empty icosahedra; and (5) orthorhombic CaAu6.09(2)Al6.01(1) with icosahedra that are half empty and half partially occupied by Al. Electronic DOS and COHP curves were used to rationalize the structural depiction of Sr/Ca(AuxAl1–x)12–13 as icosahedra packing of (AuxAl1–x)12–13 with voids filled by the electropositive Sr/Ca.
- Research Organization:
- Ames Laboratory (AMES), Ames, IA (United States)
- Sponsoring Organization:
- USDOE; National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
- Grant/Contract Number:
- AC02-07CH11358; NSF-DMR-10-05765
- OSTI ID:
- 1734521
- Report Number(s):
- IS-J-10,369
- Journal Information:
- Zeitschrift fuer Anorganische und Allgemeine Chemie, Vol. 647, Issue 2-3; ISSN 0044-2313
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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