RESUMO
The Mössbauer spectra of alpha-Zn4Sb3, a compound that is best formulated as alpha-Zn13Sb10 or (Zn2+)13(Sb3-)6(Sb24-)2, have been measured between 5 and 120 K. The resulting six spectra have been simultaneously fit with two components in the ratio of 3:2 corresponding to the Sb3- and Sb2- ions identified in this valence semiconductor. The fits yield temperature independent isomer shifts of -8.17(2) and -9.73(2) mm/s and quadrupole interactions of -4.9(2) and 0 mm/s for the Sb3- and Sb2- ions, respectively; the corresponding Mössbauer temperatures are 197(5) and 207(5) K, temperatures that are lower than the Debye temperature of beta-Zn4Sb3. The isomer shifts correspond to electronic configurations between 5s25p6 and 5s1.755p4.01 for the Sb3- ions and between 5s25p5 and 5s1.805p3.38 for the Sb2- ions, configurations that are in good agreement with the expected configurations for this valence semiconductor and with the results of band structure calculations.