Chemical substitution of Zn in the structure of ordered Cu6Zn2Sb2: A structural and theoretical study

Abstract

A series of new ternary compounds with composition Cu6-xZn2+xSb2 (0.0 ≤ x ≤ 1.0) are synthesized by high-temperature solid-state method. Phase homogeneity that ranges from Cu5Zn3Sb2 to Cu6Zn2Sb2 [Cu6-xZn2+xSb2 (0.0 ≤ x ≤ 1.0)] is determined by X-ray diffraction technique and energy dispersive X-ray analysis. The structure and stability of ordered Cu6Zn2Sb2 have recently been reported. The atomic ordering of two neighboring elements Cu and Zn has been addressed in the previous report. In this study, two compounds, Cu5Zn3Sb2 and Cu5.5Zn2.5Sb2 that formed due to the specific chemical substitution of Cu by Zn have been structurally characterized. Like Cu6Zn2Sb2, both the compounds adopt TiAl3Ge structure type (P4/nmm (129)). Specific substitution pattern of Zn to Cu site has been confirmed by both neutron diffraction and first principle total energy calculations. The structure of Cu6Zn2Sb2 is viewed as alternating units of Cu2Sb and CsCl type CuZn. For the observed composition range - Cu6-xZn2+xSb2 (0 ≤ x ≤ 1.0), Cu site in CuZn unit is unaffected by chemical substitution, whereas the Cu site in Cu2Sb unit undergoes chemical substitution by Zn.

Department(s)

Chemistry and Biochemistry

Document Type

Article

DOI

https://doi.org/10.1016/j.solidstatesciences.2020.106333

Keywords

Atomic ordering, First principle total energy calculation., Intermetallic alloys, Neutron diffraction, Site preference, X-ray diffraction

Publication Date

9-1-2020

Journal Title

Solid State Sciences

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