Chemical and structural properties of the system (1-x)Fe2O3 + xNd(2)O(3), 0 less than or equal to x less than or equal to 1, were investigated using X-ray diffraction, Fe-57 Mossbauer spectroscopy and Fourier transform-infrared (FT-IR) spectroscopy. The samples were prepared by the chemical coprecipitation and thermal treatment of Fe(OH)(3)/Nd(OH)(3) coprecipitates. X-ray diffraction showed the presence of oxide phases alpha-Fe2O3 + NdFeO3 in the Fe2O3-rich region, and the oxide phases Nd2O3 + NdFeO3 in the Nd2O3-rich region. Fe-57 Mossbauer spectra were characterized with one sextet of spectral lines at room temperature. Mathematical evaluation of the Mossbauer spectra showed distinct regularities in the changes of Mossbauer parameters, thus indicating the presence of two subspectra with very similar spectral behaviour. High sensitivity of the Nd2O3 phase to the moisture and atmosphere CO2 was demonstrated by FT-IR spectroscopy.