The Mössbauer quadrupole splitting of 57Fe (II) in FeSiF 6. 6 H2O decreases with increasing temperature from 77 to 300 K and this cannot be fully explained on the basis of the static crystal field interaction only which is usually used to obtain the electronic orbital states and the resulting quadrupole interaction. In the present work we have considered the mixing between orbital states due to orbit-lattice interaction, obtained the perturbed electron-phonon states and then calculated the quadrupole splitting from these states as a function of temperature. The theoretical results thus obtained agree reasonably well with the experimental data.