Preparation and m�ssbauer studies of tetraaquabis[maleato(1-)]-iron(II)

Abstract

Tetraaquabis[maleato(1-)]iron(II), Fe(C4H3O4)2 · 4H2O has been synthesised. The compound is monomeric and is isomorphous with the manganese(II) analogue. The temperature dependence of quadrupole splitting and optical spectral data giveca. 10000 cm−1,ca. 650 cm−1,ca. 190 cm−1 andca. 1400 cm−1 for the 10 Dq, tetragonal field, rhombic field and the splitting of the Eg level, respectively. The quadrupole splitting data indicate that distortion from cubic symmetry increases in the order oxalate < malonate < maleate. DTA, TGA and Mossbauer studies indicate elimination of one molecule of maleic acid at 235 °C. The resulting product shows a less distorted structure and this is attributed to the formation of maleato(2-)iron(II).