X-ray diffraction (XRD) and Mossbauer spectroscopy techniques combined with theoretical calculations based on the Korringa-Kohn-Rostoker (KKR) electronic structure calculation method were used to investigate sigma-phase Fe100-xRex alloys (x = 43, 45, 47, 49 and 53). Structural data such as site occupancies and lattice constants were derived from the XRD patters, while the average isomer shift and distribution curves of the quadrupole splitting were obtained from the Mossbauer spectra. Fe-site charge-densities and the quadrupole splittings were computed with the KKR method for each lattice site. The calculated quantities combined with the experimentally determined site occupancies were successfully used to decompose the measured Mossbauer spectra into five components corresponding to the five sublattices. (C) 2013 Elsevier B.V. All rights reserved.