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BaAu(x)Zn(13-x): electron-poor cubic NaZn13-type intermetallic and its ordered tetragonal variant
Shalabh Gupta1, John D Corbett
1Ames Laboratory and Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.
Inorganic Chemistry
|February 9, 2012
Summary
We synthesized and characterized novel cubic and tetragonal BaAu(x)Zn(13-x) compounds. Ordering of gold and zinc in the tetragonal phase enhances heteroatomic contacts and electronic properties, indicating metallic behavior.
Area of Science:
- Solid-state chemistry and materials science
- Crystallography and structural characterization
- Computational materials science and electronic structure
Background:
- Exploration of intermetallic compounds with potential for unique electronic and structural properties.
- Previous studies on NaZn(13)-type structures and their variations.
- Understanding the role of atomic ordering in determining material characteristics.
Purpose of the Study:
- To synthesize and characterize new cubic and tetragonal BaAu(x)Zn(13-x) compounds.
- To investigate the structural differences between cubic and tetragonal phases, focusing on atomic ordering.
- To analyze the electronic structure and bonding characteristics of the synthesized materials.
Main Methods:
- Synthesis of BaAu(x)Zn(13-x) compounds across specific composition ranges.
- X-ray diffraction for structural determination and phase identification.
- Linear Muffin-Tin Orbital (LMTO) based electronic structure calculations and analysis of Hamilton populations (-ICOHPs).
Main Results:
- Successful synthesis of cubic NaZn(13)-type BaAu(x)Zn(13-x) (1 ≤ x ≤ 5.4 and 6.4 ≤ x ≤ 8) and an ordered tetragonal variant near x = 6.
- The tetragonal phase exhibits ordered icosahedra and distinct coloring schemes for tetrahedral stars (TS), unlike the mixed cubic phase.
- Electronic structure calculations reveal enhanced heteroatomic Au-Zn bonding and larger overlap populations in the tetragonal phase, suggesting metallic properties with dispersed Au d bands and free-electron-like s and p bands.
Conclusions:
- The study successfully synthesized and characterized novel cubic and tetragonal phases of BaAu(x)Zn(13-x).
- Atomic ordering in the tetragonal phase significantly influences bonding and electronic properties, leading to enhanced Au-Zn interactions.
- The synthesized materials exhibit metallic characteristics, making them of interest for further electronic applications.
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