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  • Author or Editor: R. Garg x
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Abstract  

A series of carboxylatoferrate (III) complexes have been synthesized with monocarboxylic and dicarboxylic acids. Mössbauer spectra of all the complexes exhibit quadrupole doublets with EQ=0.36–0.88 mm s–1, suggesting a distorted octahedral geometry. The complexes start decomposing at 100°C and finally yield a constant weight at <500°C. Mössbauer spectral studies of the intermediates and final products after heating at different temperatures yield a complex pattern, suggesting the formation of one or two magnetic phases. Mössbauer spectra of the final products show two, six or eight lines with a central doublet, all indicating the formation of -Fe2O3 of different particle sizes. It is proposed that decarboxylation occurs first, followed by the loss of one or two ligands, depending on the nature of the carboxylate and the heating tempeature. The complex of pyridine-2,6-dicarboxylic acid shows an anomalous behavior.

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Abstract  

A thermal neutron activation method has been developed for the determination of Cu in Cu–Pb–Zn ores and chalcopyrite ore concentrates using the reaction63Cu(N, )64Cu. The samples were irradiated with thermal neutrons from an241Am–Be neutron source and the annihilation -radiations of 0.511 MeV were counted on 3×3 NaI(T1) detector coupled with single channel pulse height analyzer. The method is nondestructive, economical and ideal for bulk analysis of ores with 1–16% Cu.

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Abstract  

Gamma-ray induced decomposition of solid binary mixtures of KNO3 with halides viz. KCl, KBr and KI has been studied at room temperature. G(NO 2 ) values were found to vary with absorbed dose. Size and electronegativity of anions and molar composition of halides are the other factors influencing radiolysis.

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Abstract  

Mössbauer spectra of hexakis (trimethylacetato) ferrate(III) complexes with general formula M3[Fe{OCOC(CH3)3}6] (where M=H+, Li+, Na+, K+ and NH 4 + ) exhibit a quadrupole doublet with EQ=0.31–0.65 mms–1 and =0.60–0.74 mms–1 (with respect to S.N.P. as standard). Infrared studies suggest unidentate coordination of the carboxylate ligands. Anomalously high and EQ values for H3[Fe{OCOC(CH3)3}6] have been explained in terms of possible hydrogen bonding. Thermal decomposition studies show fast and single stage decomposition yielding a constant weight at 320°C. Mössbauer spectra of intermediates after heating complexes at different temperatures indicate increasing EQ values. At 350°C, all complexes exhibit six-line spectra, suggesting the formation of alkali metal ferrate (Na2O·NaFeO2) or Fe2O3.

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Abstract  

Knowledge of occurrence and concentration of trace elements in dust particulates from and around industrial establishments is essential to know the source of pollutants and atmosphere quality. Dust particulates from two cement factories in the central part of India were analyzed for 5 minor (Cl, Fe, K, Mg, Na) and 23 trace elements (Ag, As, Ba, Br, Cd, Co, Cr, Cs, Dy, Eu, Ga, Hf, Hg, La, Mn, Sb, Sc, Se, Sm, Sr, Th, W and Zn) by INAA and RNAA techniques. Significant differences have been observed for some toxic trace elements at different locations. Mn content is particularly high in all the dust particulates. Urban particulate (SRM 1648) and Coal fly ash (SRM 1633a) from NIST and Pond sediment (CRM No. 2) from NIES were also analyzed. The data have been analyzed and interpreted in terms of air quality at different locations inside the plant and two factories.

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Abstract  

Fast neutron-activation methods have been developed for the determination of iron and silicon in USGS and Indian standards and bauxites. Nuclear reactions56Fe/n, p/56Mn and28Si/n, p/28Al were carried out using241Am-Be neutron source and cutting off thermal neutrons with a Cd shield. For Si a cyclic method was adopted due to short half life of28Al /2.3 min/. The methods are non destructive, fast, economic and ideal for bulk analysis of rocks and process control.

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Abstract  

A radiochemical method for the determination of gold using198Au, has been developed. It is based on the synergistic extraction of Au(III) with thionalide (TA) in ethyl methyl ketone (EMK) or isobuthyl methyl ketone (IBMK) at pH 5.0.Effect of various parameters such as pH, nature of solvent and interferences due to other radionuclides have been studied. The method can be used up to 25 ng of Au.

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Abstract  

A radiochemical solvent extraction method has been developed for the micro determination of Mo/VI/ using99Mo tracer. It involves removal of99mTc by ethyl methyl ketone /EMK/ and extraction of Mo with tri-n-butyl phosphate /TBP/ from 5M HCl. Different parameters affecting the extraction such as pH dependence, nature of solvent and interferences due to other radionuclides have been studied. The method can be used up to 2 g of Mo.

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Abstract  

Mössbauer and infrared spectroscopic studies of a series of iron(III) complexes of dicarboxylic acids, maleic, malonic, succinic, glutaric, adipic, pimelic, suberic, azealic and sebacic have been carried out at room temperature. All complexes exhibit a quadrupole doublet with isomer shift () values in the range of 0.62 –0.72 mm·s–1 (with respect to SNP) and quadrupole splitting, EQ=0.53–0.74 mm· s–1. It is observed that tris complexes are formed up to pimelic acid, while bis complexes are formed those for the other three acids. Isomer shift () values do not vary significantly but EQ values show a somewhat regular trend. Magnetic moment data indicate high spin Fe(III) in octahedral geometry.

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