From A.F. Voigt's Thesis (Ph. D.)--University of Michigan, 1941." / "Reprinted from the Physical review, v. 60, no. 9 ... November 1, 1941."

Thesis (Ph. D.)--University of Michigan, 1935. / "Reprinted from the Physical review, vol. 49, no. 2, January 15, 1936."

Th.--Sci. phys.--Bordeaux 1, 1978. N°: 580.

This M.Sc. thesis is focused on geochemical position of lithogenic and anthropogenic thallium in forest and agricultural soils. Two localities with different contamination source were chosen for this study. The first studied locality with occurrence of lithogenic thallium only, was an area of Kluky u Písku (South Bohemia). The second studied locality with anthropogenic thallium occurrence was the area of Olkusz (South Poland). The thallium fractionation forms in studied soils were detected by a sequential extraction procedure. The significant differences in thallium distribution and mobilization were observed at both localities. It was found that the erosive and bioturbation processes, as well as dust deposition into the soils, represent the main factors for lithogenic thallium mobilization and thallium distribution between biotic and abiotic components of the environment. Dust deposition of anthropogenic thallium depends mainly on predominant wind direction in landscape, or landform of target area (presence/absence of forest etc.). Ore processing methods and an inappropriate location of disposal sites also played an important role in the mobilization/imobilization process of anthropogenic Tl and soil contamination.

Chemical speciation has become increasingly important in environmental and industrial systems, because of the difference in properties of the different physico-chemical forms of an element. In modern environmental and industrial analysis the determination of these individual species are required over and above total elemental analysis. In particular, oxidation state speciation has become a focus area of modern analytical chemistry. Hyphenated techniques where two or more analytical techniques are coupled, have been widely used in chemical speciation analysis. In particular, chromatographic techniques coupled with suitable detection systems have been proved to be very useful in trace element speciation. In this study, modified hyphenated techniques have been proposed for vanadium and thallium speciation. Two main species of vanadium, V(IV) and V(V) as a redox couple are widely used in petrochemical industries for the removal of sulphur. The effectiveness of vanadium as a catalyst is dependent on the ratio of the two species. Ion chromatography with an anion exchange column as the separation system, followed by ICP-OES detection at the wavelength of 309.311 nm has been proposed for the determination of the two species. In this method, EDTA was used for the stabilization of V(IV) and for the formation of V(IV) and V(V) EDTA complexes, which can be separated readily by means of a Dionex anion exchange column (AG5 guard column). The detection limits were 0.02 mg/L for V(IV), and 0.05 mg/L for V(V). The use of an ultrasonic nebulizer can enhance the sensitivity and therefore improve detection limits to as low as 2 ƒÝg/L for both species. The method is fast, cost-effective and interference free and was successfully used in the analysis of complex industrial samples. Thallium speciation is important because thallium species have accumulative toxicity to humans. No methods for the simultaneous separation and determination of thallium species could be found in the chemical literature. In this research, a new hyphenated method, namely HPLC coupled with ICP-OES was developed for the simultaneous separation and determination of the two thallium species, Tl(I) and Tl(III). DTPA was used in this method for stabilizing Tl(III) by formation of an anionic Tl(III)-DTPA complex. After stabilization, the two species were separated by using a Dionex cation exchange column, CG12A guard column, followed by ICP-OES detection at the wavelength of 351.924 nm. The detection limits were 0.8 mg/L and 0.1 mg/L for both species when using a V-groove nebulizer and ultrasonic nebulizer, respectively. No spectral interferences were observed. Only iodide can cause a chemical interference by forming a precipitate with Tl(I). / Prof. P.P. Coetzee

The kinetics of the oxidation of HCOOH by thallium (ill) in aqueous perchloric acid solution were studied in the temperature range 65 to 85°C. The effects of concentration variation, ionic strength, pH and various salts on the rate of reaction were determined. The kinetics suggest that the reaction proceeds through the formation of an intermediate complex Tl.HCOOH⁺⁺⁺ by the following mechanism T1⁺⁺⁺ + HCOOH ⇄T1.HCOOH⁺⁺⁺ (K fast equilibrium) T1HCOOH⁺⁺⁺ → T1⁺ + 2H⁺ + CO₂ (k slow) On the basis of this mechanism, the following rate equation was derived and found to fit the experimental data. [Equation omitted] where a and b are the initial T1⁺⁺⁺ and HCOOH concentrations, respectively, while x is the concentration of T1⁺ at time t. The constants k and K were evaluated kinetically and found to have the values: K = 16.2 liter mole¯¹ (between 65 and 85°C.) and k = 1.2 x 10¹³ exp, [-26,600/RT] sec.¯¹. The absorption spectra of the solutions also provided evidence for the presence of the postulated complex. The inhibiting effects of chloride and sulphate ions on the reaction were attributed to their ability to tie up thallium (III) by complexing with it. / Science, Faculty of / Chemistry, Department of / Graduate

Nuclear magnetic resonance studies in single crystals of thallium have been performed for the first time. The resonance frequency, line width and second moment were studied as a function of crystal orientation with respect to the magnetic field. The Knight shift parameters were determined at liquid helium and liquid nitrogen temperatures. The anisotropic Knight shift results were in disagreement with the results obtained on powder specimens by other workers. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The atomic spectra of Thallium were excited and photographed in the spectral region from 340 to 9000 Å , using both an electrodeless discharge and a spark-in-Helium as light sources. The single electron Rydberg series have been extended in TI III. The ionization potential of TI III and Pb IV was determined from hydrogenic terms and found to be 240773 ± 5 cm⁻¹ and 342438 ± 5 cm⁻¹ respectively. The dipole polarizability of TI III was found to be 2.53 ± .02 a³₀ and of Pb IV 4.37 ± .04 a³₀. Using a line list previously obtained in this laboratory, terms belonging to three electron configuration were established in TI III and Pb IV. The 5d⁹ ns series was extended in TI IV and an ionization potential of 412500 ± 300 cm⁻¹ arrived at. In TI IV and Pb V the two electron configurations 5d⁹ 6d, 5d⁹ 5f, 5d⁹ 7p and 5d⁸ 6s² were partially established while a number of terms belonging to the complex 5d⁸ 6s6p configuration could be identified as well. The analysis of TI II was extended by completing the 5d¹º 6p² configuration and identifying a number of odd and even parity terms above the first ionization limit. These were tentatively assigned to the 5d¹º 6p7p, 5d⁹ 6s² 7s, 5d⁹ 6s² 6d, 5d⁹6s6p² and the 5d¹º6p7s configurations. The number of classified TI III lines, involved in this extension of the term analysis, has increased from 247 to 579. In the TI IV spectrum the increase in classified lines has been from 35 to 308 lines. In lead spectra the increase in Pb IV has been from 134 lines to 460, and in Pb V the corresponding increase is from 200 to 303 lines. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

The vacuum pyrolysis of Tl₂R¹R²C₂B₉H₉(R¹=R²=H; R¹=H, R²=CH₃; R¹R²=CH₃) species yielded some interesting thallium-containing heterocarboranes. The major pyrolysis products are thallium metal and TlR¹R²C₂B₉H₁₀. Hydrogen and the corresponding closo-carboranes, R¹R²C₂B₉H₉, were produced as minor products. The reactions of Tl₂R¹R²C₂B₉H₁₀ compounds with weak organic acids yielded the identical Tl₂R¹R²C₂B₉H₁₀ products that were produced by vacuum pyrolysis. The action of strong protic acids on Tl₂R¹R²C₂B₉H₉ produced the nido-carboranes, R¹R²C₂B₉H₉. The mechanism of the pyrolysis reaction and the proposed structures of the Tl₂R¹R²C₂B₉H₁₀ compounds are discussed. The compounds were identified by ¹H and ¹⁹B NMR, IR, mass spectrometry, and elemental analysis. / Master of Science