I-129 and Au-197 Mossbauer Spectroscopy of AuI and AgAuI2

Abstract

Mossbauer spectroscopy of 129I and 197Au nuclei has been applied for AuI and AgAuI2 to clarify the electronic structures of the gold and iodine atoms, and to investigate the nature of the Au-I bonds. In the 129I Mossbauer spectra the sign of e2qQ is positive for AuI, whereas the sign is negative for AgAuI2. This is attributable to the difference in molecular structures: The iodine atom in AuI is bridged by two gold atoms and in AgAuI2 the iodine is terminal. The 197Au Mossbauer spectra suggest that the Au-I bond in AgAuI2 is more covalent than that in AuI. We have revealed that AgAuI2 consists of Ag+ and linear [I-Au-I] - units from the Rietveld refinement of the X-ray powder diffraction pattern. © 2014, Verlag der Zeitschrift für Naturforschung. All rights reserved.