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Abstract  

Destructive and non-destructive methods have been used for the determination of microtraces of antimony in high-purity silicon powder. The destructive method was based on substoichiometric radioactivation analysis with solvent extraction using BPHA and cupferron as organic reagents. The antimony contents in high-purity silicon can be determined by the proposed method.

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Abstract  

Neutron activation analysis has been applied to the determination of ultra-trace amounts of arsenic based on the substoichiometric extraction of As(III) with thionalide. The arsenic content in high-purity trichlorosilane or silicon can be determined by the proposed method down to sub-ppb range with a very good reproducibility. Also, the data obtained were compared with results from atomic absorption spectrophotometry.

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Abstract  

Dibutyl-and monobutylphosphoric acid in acidic toluene medium were determined by ion chromatography. The procedure involved stripping with dilute sodium hydroxide solution and used carbon tetrachloride as diluent, then detection with a conductivity meter. The effect of flow rate, eluent strength and stripping solution, the effect of chloride and nitrate ion on DBP, the effect on DBP in sodium hydroxide solution, and the effect of organic aliphatic acids were discussed. The detection limits of 0.19 ppm and 0.14 ppm were found for DBP and MBP, respectively.

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Abstract  

A method is described for the determination of gallium and other trace elements such as Ce, Cr, Hf, Lu and Th in bauxite by the technique of neutron activation analysis using gold as internal standard. Isopropyl ether was used as organic extractant to extract radioactive gallium from the sample. This method yields very good accuracy with a relative error of ±3%.

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Abstract  

Some criterions in order thatl 1 embeds complementably inE Φ(μ) and inL Φ(μ) are given. It is also proved that every idealL inL Φ(μ) such thatI Φ(x/‖x‖Φ)=1 for anyxεL/{0} is contained inE Φ(μ).

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Abstract  

Radiobrominations of cetyl bromide with82Br in several organic media such as DMF, 18-crown-6, DMSO, pyridine and n-butanol were achieved and a comparison was made as to the labelling rates. The rate order was found as follows: DMF>18-crown-6>DMSO>pyridine } n-butanol which was attributed to increased anion /i.e., the nucleophilic bromide ion,82Br/ solvation. Labelling in pyridine or alcohol was found to be too slow to meet practical needs. A suitable crown ether such as 18-crown-6 was found to be favourable for rapid radiobromination. However, it was discovered unexpectedly that dimethylformamide /DMF/ was superior to 18-crown-6. We therefore recommend DMF as an alternative reaction medium for fast radiobromination considering that this solvent is inexpensive and readily available.

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Abstract  

Iron foil was irradiated with an 80 MeV/nucleon16O-ion beam. The foil was dissolved in hydrochloric acid, and Fe2+ in the solution was oxidized to Fe3+ with hydrogen peroxide. The solution was diluted to 6M in HCl and was passed through an anion exchange column. Washing with 6M HCl yielded a carrier- and salt-free multitracer solution covering radioactive nuclides of elements from sodium to manganese.

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Two Mn(II) chloride complexes containing guest molecules

Solvothermal syntheses, crystal structures and thermal decomposition

Journal of Thermal Analysis and Calorimetry
Authors: Q. Yang, S. Chen, and S. Gao

Abstract  

Two phenanthroline-manganese inclusion complexes with [MnCl(H2O)(phen)2]+ core have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric analyses. Uncoordinated 2-mercaptothiazole (tzdtH) and 2-mercaptobenzothiazole (bztzH) as guest molecules are included in the complexes with formulas [MnCl(H2O)(phen)2]Cl·tzdtH (1) and {[MnCl(H2O)(phen)2]Cl}2·bztzH (2). X-ray structural analyses for complexes revealed that the complex 1 is triclinic, space group P1 with a=9.724(1) Å, b=11.858(1) Å, c=12.644(2) Å; β=89.056(2)°; Z=2, D c=1.513 Mg m−3, F(000)=638 and the complex 2 is triclinic, space group P1 with a=9.861(1) Å, b=11.476(1) Å; c=12.908(3) Å; β=84.991(2)°; Z=1, D c=1.511 Mg m−3, F(000)=600. Two complexes exhibit high stability up to 650°C. The molar specific heat capacities for the two complexes 1 and 2 can be estimated as being 96.175±0.332 and 72.505±0.364 J mol−1 K−1 at 298.15 K by RD496-III microcalorimeter, respectively.

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Abstract  

A new complex, diaquadi(1,2,4-triazol-5-one)zinc(II) ion nitrate formulated as {[Zn(TO)2(H2O)2](NO3)2}n (1) (1,2,4-triazole-5-one, abbreviated as: TO) was synthesized and characterized by elemental analysis, X-ray single crystal diffraction, infrared spectrum (IR), differential scanning calorimetry (DSC), thermogravimetric analysis and differential thermogravimetric analysis (TG-DTG). The X-ray structure analysis reveals that the complex is orthorhombic with space group Pbca and unit-cell parameters a=6.9504(2) �; b=10.6473(3) �; c=17.8555(5) �. Based on the result of thermal analysis, the thermal decomposition process of the compound was derived. From measurement of the enthalpy of solution in water in 298.15 K, the standard molar enthalpy of solution of lignand TO and the complex were determined as 15.43�0.18 and 52.64�0.42 kJ mol−1, respectively. In addition, the standard molar enthalpy of formation of TO(aq) was calculated as −126.97�0.72 kJ mol−1.

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Abstract  

Five new complexes M(Hmna)2 [M=Mn(II) (1), Co(II) (2), Ni(II) (3), Cu(II) (4) and Zn(II) (5), H2mna=2-mercaptonicotinic acid] have been synthesized and characterized by elemental analyses, IR spectra, thermogravimetric analyses. In addition, molar specific heat capacities and enthalpy changes of reactions were determined by a microcalorimeter at 298.15 K. All the complexes exhibited similar IR spectra, the sulfur and oxygen atoms from monoanionic Hmna ligand coordinated to M2+ in a bidentate fashion. The thermal stability of M(Hmna)2 complexes varied in the sequence 1>2>3>4>5. The complexes were stable up to about 300°C and decomposed to oxides at higher temperatures. The molar specific heat capacities of the complexes were determined in the range between 106.452±0.399 and 145.920±0.423 J mol−1 K−1. The enthalpy changes of reactions, Δr H m θ, were determined from 18.28±0.05 to 52.59±0.07 kJ mol−1 for complexes 1–5, indicating that the thermodynamic stability of M(Hmna)2 increased in the sequence from Mn2+ to Zn2+.

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