5 7 Fe Mossbauer spectra have been recorded for Nd 1 6 Fe 7 6 - x Sn x B 8 samples (x = 0, 1, 2, 3 and 4) at room temperature. The dependence of e 5 7 Fe hyperfine magnetic fields on Sn concentration was obtained by analysing the Mossbauer spectra. The site preference of Sn atom is discussed using Mossbauer spectroscopy. The variation of lattice parameters with Sn concentration and the solubility of Sn in the Nd 2 Fe 1 4 B phase were studied using powder X-ray diffraction analysis. The variation of Curie temperature with Sn concentration was determined using the differential scanning calorimetry technique.