A Promising Thermoelectric Material:  Zn₄Sb₃ or Zn_6-δSb₅. Its Composition, Structure, Stability, and Polymorphs. Structure and Stability of Zn_1-δSb

Abstract

Composition, crystal structure, and stability of the thermoelectric material, known in the literature as "Zn 4 Sb 3 ", has been characterized using low-and room-temperature single-crystal X-ray diffraction techniques, as well as in situ room-and high-temperature powder X-ray diffraction methods. We have found that the Zn 4 Sb 3 phase does not exist below 767 K (the β−γ transition temperature); it is the Zn 6-δ Sb 5 phase that is erroneously assigned the Zn 4 Sb 3 composition and is considered to be a promising thermoelectric material. The structure of Zn 6-δ Sb 5 is similar to that of "Zn 4 Sb 3 " but no Zn/Sb mixture is observed on any Sb site. Instead, a significant deficiency on the Zn site is discovered. There are two, not one, as previously reported, Zn 6-δ Sb 5 polymorphs below room temperature. In dynamic vacuum and at elevated temperatures the Zn 6-δ Sb 5 phase becomes zinc poorer due to zinc sublimation and eventually decomposes into ZnSb and Zn before reaching its melting temperature of 841 K. The binary Zn 1-δ Sb compound also loses zinc in dynamic vacuum and at high temperatures and decomposes into Sb and Zn. The structure of Zn 1-δ Sb (CdSb-type) is analyzed using powder X-ray diffraction techniques. Disciplines

Phase Selection and Microstructure Refinement of Melt-Spun Zn4Sb3-Type Compound

“…Furthermore, the low intensity of the pattern and the relative high value of baseline at low angle reflections, suggests the presence of amorphous phases consistent with the rapid solidification proper of the melt spinning process. The values obtained for the lattice parameters of the rhombohedral cell (R,-3c) are in agreement (a = 1.2228 nm, c = 1.2424 nm) with those reported in the literature for the ε -Zn 4 Sb 3 phase [10,11].…”

Review of Research on the Thermoelectric Material ZnSb

“…61. The structure of ZnSb has been studied and confirmed by different techniques, albeit gave slightly different interatomic distances [25][26][27][28]. Figure 2 shows the crystal structure of ZnSb that was generated by the structural data from Mozharivskyj [27].…”

“…Song, 2016.) (a) Structure in a 1×2×3 cell generated by Mozharivskyj's data [27]. Both the deformed tetrahedra and the Zn 2 Sb 2 -ring, as well as the interatomic distances between the nearest neighbours are annotated.…”

Physical properties of thermoelectric zinc antimonide using first-principles calculations

“…From an experimental point of view, this possibility could be checked only with high precision diffraction experiments on single-crystals. Actually, there is only one experimental work in which the ADPs have been determined [73].…”