The system of ferroelectric solid solutions (SnxPb1−x)2P2S6 with x = 0.95; 0.9; 0.8; 0.6; 0.5; 0.4 is studied by means of the Mössbauer effect on 119Sn nuclei at room temperature. In the region of the ferroelectric phase transition kinks in the concentration dependencies of the line width, Mössbauer spectrum area, absolute Mössbauer effect probability, effective Debye temperature, and mean‐square displacements of tin atoms from equilibrium have been observed. The isomer shift increases linearly with the increase of lead concentration.