Role of the water of crystallization in the Mössbauer spectra of some low-spin ferric and high-spin ferrous compounds. Its implications in comparative studies

Mössbauer spectra of low-spin ferric and high-spin ferrous compounds may be sensitive to the local humidity during the measuring process or to other parameters associated with the hydration degree of the sample. This effect is related to the location of water molecules around the t_2g orbitals (d_xy, d_xz, d_yz). The results indicate that for comparative studies all Mössbauer measurements must be carried out in well standardized conditions.