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- Author or Editor: Sandeep Kaur x
- Chemistry and Chemical Engineering x
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Abstract
Thermal decomposition of ammonium tris (malonato) ferrate (III) tetrahydrate, i. e. (NH4)3[Fe(CH2C2O4)3]·4H2O has been studied up to 973 K in static air atmosphere employing Mössbauer and infrared spectroscopies, and non-isothermal techniques (TG, DTG, DTA). The anhydrous complex decomposes into an iron (II) intermediate at 453 K. The iron (II) species on further heating is reoxidized to 
-Fe2O3 as the final thermolysis product. An increase in particle size of -Fe2O3 with increasing decomposition temperature has been observed. The results are compared with the analogous oxalate complex.
Abstract
Thermal decomposition of lithium tris (malonato) ferrate (III) tetrahydrate i.e. Li3[Fe(CH2C2O4)3].4H2O has been studied in the temperature range of 353–873 K in static air atmosphere using Mössbauer, infrared spectroscopy and nonisothermal techniques (TG-DTG-DTA). The anhydrous complex decomposed into ferric oxide of varying particle sizes and alkali metal malonates/carbonates in succesive stages. Fimally a solid state reaction between 
-Fe2O3 and alkali metal carbonate gives fine particles of lithium ferrite (LiFeO2) at a temperature lower than for oxalate precursor and for ceramic method.
Abstract
Thermal decomposition of some alkali tris (malonato) ferrate (III) tetrahydrates, i. e. M3 [Fe(CH2C2O4)3]·4H2O (M=Na, K) has been studied in the temperature range of 433–973 K in static air atmosphere using Mössbauer, IR and TG-DTG-DTA techniques. Mössbauer spectra are reported at different stages to study the mechanism of decomposition. The anhydrous complex decomposed into -Fe2O3 of varying particle sizes and alkali metal malonate/carbonate in successive stages. In the final stage of remixing of cations, a solid state reaction between -Fe2O3 and alkali metal carbonate/oxide gives fine particles of the respective ferrites at temperatures lower than for oxalate precursor or even for ceramic method. Thermal stability obeys the order: sodium > potassium > lithium tris(malonato) ferrate (III).
Abstract
Mössbauer spectra of a series of the complexes of the type Na3[Fe/RCOO/6]xH2O /R=H, CH3, C2H5, C6H5/ has been recorded at 298±2 K. All display a quadrupole doublet with isomer shift and quadrupole splitting values in agreement with high spin iron/III/ octahedral geometry. The quadrupole splitting show an increasing trend with increasing polarizability of the substituent anion /RCOO–/. A linear correlation between quadrupole splitting values and the /Fe–O/ stretching frequencies has also been observed.
Abstract
The thermal decomposition of sodium hexa-carboxylato/ferrates/III/ i.e. Na3[Fe/RCOO/6].xH2O /R=H, CH3, C2H5/ has been studied at various temperatures in air employing Mössbauer and infrared spectroscopies and non-isothermal techniques /DTG, DTA, TG/. The thermolysis proceeds without undergoing the formation of any iron/II/ intermediate. The particle size of α-Fe2O3 formed during thermolysis shows an increasing trend with increasing decomposition temperature. At higher temperatures α-NaFeO2 is formed as the ultimate product for all the complexes.
Abstract
Solid state photolysis of alkaline earth tris/malonato/ferrates/III/, i.e., M3[Fe(CH2C2O4)3]2.xH2O /M=Mg, Ca, Sr, Ba/ has been investigated employing Mössbauer, infrared and reflectance spectroscopic techniques. The complexes were irradiated for 400 h using a medium pressure mercury vapour lamp of 250 Watts. Photoreduction led to the formation of M[FeII(CH2C2O4)2(H2O)2]. The extent of photoreduction showed the following order: Ca>Sr>Mg>Ba. The results have been compared with those of analogous alkaline earth tris/oxalato/ferrates/III/.
