The structure of α-Zn4Sb3:: Ordering of the phonon-glass thermoelectric material β-Zn4Sb3

β-Zn4Sb3 is an outstanding thermoelectric material mainly due to its extraordinarily low thermal conductivity, which is similar to that of glasses. Recently it was proposed that interstitial Zn atoms are responsible for this peculiar behavior. Here we report on the crystal and electronic stucture of the low-temperature polymorph α-Zn4Sb3. During the reversible phase transition the intricate disorder in β-Zn4Sb3 disappears, and all Zn atoms localize completely. The electronic structure of α-Zn4Sb3 corresponds to that of a narrow-gap semiconductor. Copyright © 2004 American Chemical Society.