[en] Recently Sharma et al (1978) have reported the synthesis of N-p-methyl benzene oxamic acid (NPMBOA) or p-toluidinyl oxamic acid (PTOXA) and potentiometric evidences for the formation of 1:3 Ln(iii)-NPMBOA complexes. In continuation to this work the analytical aspects of this reagent in the gravimetric estimations of lanthanides and in their separation from transitional metals, using some masking agent are reported. The complexes of lanthanides with N-p-methyl benzene oxamic acid possess higher molecular weights and have been found to be insoluble in aqueous as well as non-aqueous media, hence, reagent has been tried as a precipitant for the gravimetric determination of some Lanthanide ions. (author)

[en] The reaction between indium (III) and chromotrope 2R has been studied spectrophotometrically. The absorption maximum is at 580 nm against reagent blank at pH 3.4, 0.1, Beer's law is obeyed over the concentration range 1.7-7.3 ppm of indium. The chelate has composition of 1; 2 and the value of log k is 8.65 + 0.05 (30⁰). The apparent molar extinction coefficient and Sandell's sensitivity of the reaction are 17, 312 and 0.004 kg/Cm². The effect due to 20 cations and 10 anions have been examined. The reaction has been applied to the spectrophotometric determination of indium. (author)

[en] Five organic dyes viz, Chromotrope 2R, Gallion, Eriochrome Blue SE, Eriochrome Black T and Pyrocatechol Violet form coloured complexes with scandium, which have different colours than the dye under the conditions. Spectrophotometric determination of scandium is recommended for which adherence to Beer's law limits, sensitivity, molar extinction coefficient, and the interference of the foreign ions and the limit of tolerance is described. (author)

[en] The review presents the basic concepts of radiation processing. It describes in brief the types of radiation, its interaction with matter, its sources and uses, and its hazard and protection. (author)

[en] The kinetics of adsorption of iodide ions from bulk to the surface of thorium oxide has been studied by labelling the KI solution with ¹³¹I in different concentration range 10^-2M to 10^-3M, at different pH values of KI solution (3.5 to 10.1) and after irradiating the oxide sample for 12 to 48 hours by 300 mc (Ra-Be) neutron source. The adsorption obeys Freundlich adsorption isotherm and the kinetics of adsorption is found to be of first order. The effect of irradiation with neutrons and γ-rays on the adsorbent and the variation in pH of the solution influence the extent of adsorption and the rates show first order kinetics in both the cases. (auth.)

[en] A few new hepta-coordinated mixed ligand complexes of the type Ln(L)₁(L')₃Cl₂ Cl.3H₂O where Ln = Y(III), La(III), Pr(III), Nd(III), Sm(III), Eu(III), Cd(III) and Dy(III), L = dimethylglyoxime and L' = N-phenyl or N.N'-diphenylthiourea have been prepared and characterised by a study of elemental, spectral (electronic and infrared), thermal (DTA, TGA) and conductivity measurements. The nature of the bonding has been established by a study of infrared spectra and it was found that the second ligand is bonded to the lanthanide ion through sulphur. Thermal data indicated the presence of water molecules as lattice water. Conductivity measurements in methanol and dimethyl-formamide show that all the mixed complexes are 1:1 electrolytes. However, in dimethylsulphoxide they showed a 1:2 electrolyte system. (author)

[en] Radioactive materials are very widely used in medicine, industry, agriculture and scientific and industrial research besides their use as nuclear weapons. The radiation energy emitted from radioactive materials into the environment has severe hazards. Because of their unique characteristics, the contamination caused by them is not comparable to other commonly known pollutions. This paper deals with various salient features of the radioactive materials, their frequent applications, the degree of hazards due to contamination in the environment and the essential safety measures to be taken in handling and disposing of the radioactive materials. (auth.)

[en] Mixed ligand chelates of the 1:1 trivalent lanthanoids-EDTA, HEDTA and NTA chelates-1, 2-Dihydroxybenzene (Pyrocatechol) have been investigated at 35degC and 0.2 M ionic strength maintained by NaC10₄. The formation of mixed ligand chelates has been found in all cases. The formation of mixed ligand chelates with EDTA shows the coordination number of lanthanoids to be eight, while the mixed ligand chelates with HEDTA and NTA shows the coordination number to be seven and six respectively. The stability constants of mixed ligand chelates are smaller than the binary complexes. The order of stability constants with respect to primary ligands follows the order NTA>HEDTA>EDTA. With respect to metal ions the stability constants increases with the decrease in ionic radii such as Gd< Er< Yb. (author)

[en] Irving Rossotti's pH-titration technique has been modified so as to make it applicable to the study of mixed ligand complexes. Stability constants of Sc(III), Y(III), La(III), Pr(III), Nd(III) and Sm(III) with amino-polycarboxylic acids (NTA, HEDTA and EDTA) as primary ligands and polyhydroxyphenols (PYC, PYG, GA, tiron, DHNSA, CA and di-SNA-DNS) as secondary ligand are evaluated. Formation of mixed ligand complex was observed in all the cases except in the case of CA and di-SNA-DNS in which two phenoxide groups are in 1,8-position and thus the six-membered chelate ring is to be formed so as to achieve mixed ligand complexation while in rest of the cases phenoxide groups are in ortho-position which can easily form a five membered chelate ring. For comparison purposes, study was extended to binary complexes under identical conditions. The trend of stability constants followed the order binary > NTA > HEDTA > EDTA which can reasonably be explained on the basis of space available for the secondary ligand and electrostatic forces between primary complex (metal ion binary system) and secondary ligand. In terms of secondary ligand it follows the order tiron > DHNSA > PYC > GA > PYG which can again be explained on the basis of the basicity of the ligand and due to various substitutions to PYC. Stability increases with the decrease in ionic radii and vice-versa i.e. Sc(III) > Y(III) > Sm(III) > Nd(III) > Pr(III) > La(III). The formation of mixed-ligand complex with various primary ligands selected for the study shows the gradual increase in coordination number from six to eight by replacement of water molecules from seven and eight coordination sites. (author)

[en] A rapid method for the extraction and simultaneous spectrophotometric determination of molybdenum (VI) with N-p-tolyl-O-methoxyben-zohydroxamic acid has been described. The molybdenum can be determined in ppm level and extracted with the reagent in isoamyl alcohol at the pH 2.5-3.5. It gives a yellow extract having lambda max at 355 nm and obeys Beer's law over the range 0.3-11 ppm. (auth.)