1H NMR Spectra of Phenylthallium (III) Crown-Ether Complexes, [C6H5Tl (III)(Crown)X]n(ClO4) (n=1 OR 2); Trans Influence of The X Groups

Abstract

Trans influence of the X groups on the spin-pin coupling constants between the thallium nucleus and the meta protons of the phenyl group attached to the thallium atom, J(Tl-H^m), were studied for a number of phenylthallium (III) crown-ether complexes, [C₆H₅Tl (III) (crown)X]n(ClO₄) (n=1 or 2).     

The Determination Of Thallium In Human Hair By Graphite Furnace Atomic Absorption Spectrophotometry

Abstract

An atomic absorption spectrophotometric procedure is des-scribed for the rapid determination of thallium in human hair. Samples of 500 μg are dissolved in nitric acid and treated with hydrogen peroxide. Aliquots of 10 μL are then analyzed using electrothermal atomization in a graphite tube furnace. The characteristic concentration for the method is 1 mg Tl kg^?1 which is adequate for forensic investigation. The relative standard deviation for a series of signals from a hair sample spiked to contain 32 mg Tl^?1 kg was 3 per cent.     

Determination of Thallium In Solid Environmental Samples By Electrothermal Atomic Absorption Spectrometry

Abstract

A method for the determination of thallium in solid environmental samples is developed. After destruction of the sample, TI(III) is extracted from 0.5 M hydrobromic acid solution into diisopropyl-ether. the organic phase is evaporated and the residue taken up in a mixture of sulfuric and nitric acids. Measurements are carried out with an atomic absorption spectrometer with Zeeman background corrector. the accuracy of the method is tested by analysis of certified reference materials and the method is applied to fly ash and emitted particulate matter from a municipal refuse incinerator and to soil samples.     

Synthesis and Applications of Poly(Acrylphenylamidrazone-Phenyl-Hydrazide-Acylphenylhydrazine) Chelating Fiber for Preconcentration and Separation of Trae In(III), Zr(IV), Tl(I), V(V), Ga(III) and Ti(IV) from Solution Samples

 An ICP-OES method using a new poly (acrylphenylamidrazone-phenylhydrazide-acylphenylhydrazine) chelating fiber to preconcentrate and separate trace In(III), Zr(IV), Tl(I), V(V), Ga(III) and Ti(IV) ions from solution samples has been established. The new chelating fiber was synthesized using polyacrylonitrile fiber as a starting material and the structure of the chelating fiber was determined by FT infrared spectrometry. The acidity, adsorption rate, re-use, capacity and interference on the adsorption of ions on the chelating fiber as well as the conditions of desorption of these ions from the chelating fiber were investigated by means of inductively coupled plasma optical emission spectrometry (ICP-OES). The results show that the relative standard deviations for the determination of 10 ng/ml In, Tl, Ga and 1 ng/ml Zr, V, Ti were lower than 2.5%. The results obtained for these ions in real solution samples by this method were basically in agreement with the given values with average errors of less than 4%. Received November 29, 2000. Revision May 22, 2001.     

The Crystal Structures of Thallium(I) Fluoride

The effects of temperature and pressure on the crystal structures of thallium(I) fluoride have been investigated using powder neutron diffraction, with the aim of resolving the uncertainties present in the literature. Under ambient conditions, TlF adopts an orthorhombic structure in space group Pbcm with Z=4 and cell parameters a=6.09556(8) Å, b=5.48860(7) Å, and c=5.18300(7) Å. This structure can be derived from an idealized rocksalt-type arrangement, though with extensive distortions of the anion sublattice due to the presence of the 6s² inert pair of the Tl⁺ Above 355 K TlF becomes tetragonal with Z=2, a=3.78283(2) Å, c=6.12312(5) Å, and space group P4/nmm. The behavior of the compound is also studied under hydrostatic pressure but, contrary to previous reports, no structural transition was observed and TlF remains orthorhombic up to at least 3.5 GPa. The compressibility is greatest along the a and b axes. The relationship between the ambient- and high-temperature structures of TlF is described and the influence of the inert pair discussed in relation to the massicot structured polymorph of PbO.     

[｛Pt_4(en)_4(NHCO~tBu)_4｝｛Tl(18-crown-6)｝_2](PF_6)_6的合成与晶体结构(英文)

The metallophilic attraction between closed shellor pseudo closed shell metal atoms with the configura-tion of d10,s2,d8has received considerable attentionrecently mainly because such metal-metal interactionsare closely associated with many important chemicaland physical properties such as catalysis,electronicconductivity and luminescence[1].The d8-d10-s2closed-shell metallophilic interactions and ligand functionali-ty have resulted in the formation and isolation ofmultinuclear aggregates with …     

重金属铊在环境介质中的分布及其迁移行为

铊是剧毒重金属元素,它在自然界中是典型的稀有分散金属。环境介质中铊的自然本底值较低,但随着铊矿床的开发和铊资源的广泛应用,岩矿石中的铊在自然力或人为作用下向环境介质中迁移。综述了铊在岩（矿）石、土壤、水体、动植物和人体中的分布,以及在上述环境介质及大气中的迁移行为。研究表明,人类活动是导致环境介质中铊含量增加的主要原因。铊在环境介质中的迁移是反复循环的复杂过程,通过风化、溶解、淋滤、吸收、沉降、固结等方式在环境介质中循环往复,从而危害环境生态和人体健康。铊污染应引起人们的普遍重视。     

Zur Neuuntersuchung des Phasendiagramms TlI—SnI2

Redetermination of the Phase Diagram TlI—SnI² A reinvestigation of the phase diagram TlI—SnI₂ revealed the existence of a not yet known ternary 4 : 1 compound of the formula Tl₄SnI₆, which decomposes peritectoidally at 229^°C. The congruent melting points of the other three ternary compounds in the system, Tl₃SnI₅, TlSnI₃, and TlSn₂I₅, at 329^°C, 292^°C and 307^°C, respectively, agreed well with former specifications. However the polymorphic transitions of the compounds Tl₃SnI⁵ and TlSn₂I₅ described by other authors could not be verified.     

铊污染及其生态健康效应

对铊污染及其生态效应，包括铊的地球化学特性、环境分布状况、生理毒性和人体慢性铊中毒的症状作了简要综述，分析了铊污染的来源，提出了铊污染的防治对策。     

Synthesis of 4′-Carboxy-benzo-30-crown-10 and a Thermodynamic Study of Its Complexes with Thallium and Alkali Cations in Acetonitrile Solution

A synthetic procedure has been developed for the preparation of 4-carboxy-benzo-30-crown-10. The formation of Na+, K+, Rb+, Cs+ and Tl+ complexes with the large crown ether was investigated conductometrically in acetonitrile solution at various temperatures. The formation constants of the resulting 1:1 complexes were determined from the molar conductance-mole ratio data. It was found that the stability of the complexes vary in the order Tl+ > K+ > Rb+ > Cs+ > Na+. The data obtained in this study support the existence of a wrap around structure for the above complexes in solution. The enthalpy and entropy of complexation reactions were determined from the temperature dependence of the formation constants. In all cases, the complexes were enthalpy stabilized but entropy destabilized. The resulting TS° vs. H°plot showed a fairly good linear correlation, indicating the existence of an entropy-enthalpy compensation in the large crown complexation reactions.