Isotope effects measured by mössbauer spectrometry in ferrous oxalate and perchlorate

The influence of the substitution of H by D was investigated by means of the Mössbauer effect in the compounds FeC₂O₄ O₄·2H₂ O and Fe(ClO₄)₂·6H₂ O. Isomer shifts δ and quadrupole splittings ? were measured between 90 and 300 K. An important isotope effect dependent on temperature was observed for the value of ? in oxalate. Only a slight difference for the value of δ could be determined in perchlorate. The well-known transition of the perchlorate takes place at temperatures which differ by 4 K for the deuterated and hydrogenated compounds.