Synthesis, Structure, and Thermoelectric Properties of α-Zn3Sb2 and Comparison to β-Zn13Sb10

Zn–Sb compounds (e.g., ZnSb, β-Zn13Sb10) are known to have intriguing thermoelectric properties, but studies of the Zn3Sb2 composition are largely absent. In this work, α-Zn3Sb2 was synthesized and studied via temperature-dependent synchrotron powder diffraction. The α-Zn3Sb2 phase undergoes a phase transformation to the β form at 425 °C, which is stable until melting at 590 °C. Rapid quenching was successful in stabilizing the α phase at room temperature, although all attempts to quench β-Zn3Sb2 were unsuccessful. The structure of α-Zn3Sb2 was solved using single crystal diffraction techniques and verified through Rietveld refinement of the powder data. α-Zn3Sb2 adopts a large hexagonal cell (R 3 space group, a = 15.212(2), c = 74.83(2) A) containing a well-defined framework of isolated Sb3– anions but highly disordered Zn2+ cations. Dense ingots of both the α-Zn3Sb2 and β-Zn13Sb10 phases were formed and used to characterize and compare the low temperature thermoelectric properties. Resistivity and Seeb...