Mossbauer spectroscopic studies of thermal decomposition products of hexacyanoferrate(II) complexes

969-974The Mossbauer spectra of hexacyanoferrates(II) of alkaline earth metals (Mg, Ca, Sr, Ba) and of La, Ti, Zr, Th, VO2+ and UO exhibit single line (δ = -0.08-0.20 mms-1) at room temperature. Uranyl hexacyanoferrate(II), however, exhibits a large line width (Γ= 0.53 mms-1) probably due to unresolved quadrupole splitting suggesting some interaction of UO with [Fe(CN)6]4-. In general, δ values show decreasing trend with increasing charge on the outer cations. Thermogravimetric studies upto 600ᵒC show constant weight in the range 52.0-80% except for Mg hexacyanoferrate(II) which gave 30.3% residue. An attempt has been made to identify the intermediate and end products by Mossbauer spectroscopy. It is suggested that in most cases, a mixture offerrites, oxides and carbide (Fe3C) along with iron metal may be formed as end products