Mössbauer effect studies of alkali bis(citrato)ferrates(III)

Abstract

Mossbauer spectra of alkali bis(citrato)ferrates(III) i.e. M3Fe(C 6H5O7)2. x H2O (M = Li, Na, Rb, Cs, NH4) at room temperature display a doublet, the isomer shift and quadrupole splitting values indicating these complexes to be high spin with octahedral symmetry. However, in case of K3Fe(C 6H5O7)2.4H2O a single broad absorption band has been observed. The isomer shift shows a decreasing trend with the increase in the electronegativity of the substituent cation. Isomer shift also increases with the increase in cationic size (Li+, Na+, K+, Rb+, Cs+, Na+4). A linear correlation between isomer shift and the separation C=O stretching frequencies (Δν) has also been observed.