Spectroscopic Investigations of Iron(II) and Iron(III) Oxalates

In an attempt to contribute to a better characterization of Fe-II and Fe-III oxalate complexes, an investigation of their vibrational (infrared and Raman) and Fe-57-Mossbauer spectra was performed. It is shown that the two polymorphs, alpha and beta, of FeC2O4 center dot 2H(2)O cannot be accurately differentiated with any of these spectroscopic methods, demonstrating the high structural similarity of these two crystalline forms. Partially deuterated samples of beta-FeC2O4 center dot 2H(2)O were also investigated to improve the vibrational-spectroscopic analysis. In the case of Fe-2(C2O4)(3)center dot 4H(2)O, a structural model, derived from results of combined vibrational and Mossbauer data, could be proposed. The 298 K Mossbauer spectrum for this complex is discussed in detail for the first time.