In the present work, 57Fe probe Mössbauer spectroscopy was developed to study the nickelates RNi0.98Fe0.02O3 (R = Sm,Eu,Gd,Dy) with the perovskite-like structure. The restoration method for a distribution function P(v) of the positions (v) involving individual Lorentzian lines has been used for processing and analysing the Mössbauer spectra. The P(v) profile for the nickelates, at T Gd). The observed asymmetry of the P(v) profile indicates that 57Fe atoms used as a Mössbauer probe are simultaneously stabilized in two non-equivalent crystallographic positions. This result is an indirect evidence for the existence of two types of nickel position in the insulating state of nickelate RNiO3 lattices with intermediate R3+ size, which remained questionable from diffraction methods.