Behavior Of Tl Research Articles

Anomalous Behavior of Ag(I) and Tl(I) Ions in Mobilities of Molten Nitrates

The data on internal cation mobilities, u, in the molten binary nitrate systems (M, Ag)NO3 and (M, Tl)NO3 (M=alkali metal ion) determined by Klemm's countercurrent electromigration method are reexamined. In binary alkali nitrates u is well expressed by an empirical equation u={A/(Vm – Vo)}exp(-E/RT), where Vm is the molar volume; A, Vo and E are constants nearly independent of coexisting cations. If Ag+ is contained, the uM of coexisting cations M negatively deviates from such an equation, and, on the contrary, if Tl+ is contained, the uM positively deviates. Thus, Ag+ and Tl+ having relatively high polarizabilities have the opposite effects on uM, that is tranquilization effect and agitation effect, respectively. The reason has been interpreted in terms of the high polarizabilities and the difference in the sizes of Ag+ and Tl+.

Effect of bismuth substitution on liquid formation in thallium-based superconductors

The role of bismuth substitution on phase development and melting behavior of Tl 1.1− x Bi x Ba 0.4Sr 1.6Ca 2Cu 3O 9−δ was studied. The substitution limit was x = 0.25, and low-melting liquid was formed when the limit was exceeded. The barium content of the superconductor decreased with increasing bismuth substitution, which coincided with BaBiO 3 formation. Magnetization and X-ray diffraction data revealed that the single-layer Tl compound coexists with BaBiO 3 up to x = 0.8. For selected compositions, superconductor wire was fabricated by a powder-in-tube process. The critical current density was measured and correlated with the microstructure.

Characterization of the metal ion binding helix-hairpin-helix motifs in human DNA polymerase beta by X-ray structural analysis.

X-ray crystallographic studies have shown that DNA binding by human polymerase beta (pol beta) occurs primarily through two structurally and sequentially homologous helix-hairpin-helix (HhH) motifs, one in the fingers subdomain and the other in the 8-kDa domain [Pelletier, H., Sawaya, M. R., Wolfle, W., Wilson, S. H., & Kraut, J. (1996a) Biochemistry 35, 12742-12761]. In that DNA binding by each HhH motif is facilitated by a metal ion, we set out to determine the identity of the metal ion that most likely binds to the HhH motif in vivo. Crystal soaking experiments were performed on human pol beta-DNA cocrystals with Mg2+, Ca2+, Na+, and K+, the four most prevalent metal ions in the cell, and in each case a data set was collected and the resulting structure was refined. Under the conditions tested, the HhH motifs of pol beta have an affinity for these biologically prevalent metal ions in the order Mg2+ < Ca2+ < Na+ < K+, with K+ displaying the strongest binding. Crystals soaked in the presence of Tl+, a commonly used spectroscopic probe for K+, were too X-ray-sensitive to establish the binding behavior of Tl+, but soaking experiments with Ba2+ and Cs+ resulted in relatively stable crystals that gave evidence of metal ion binding in both HhH motifs, confirming that larger monovalent and divalent metal ions are capable of binding to the HhH metal sites. Although Mn2+, which has been categorized as a potent polymerase mutagen, binds to the HhH motifs with a greater affinity than Mg2+, Mn2+ does not bind to the HhH motifs in the presence of equimolar concentrations of Na+. These results suggest that in vivo, where Mn2+ is present only in trace amounts, Mn2+ probably does not have a large effect on DNA binding and may instead manifest a mutagenic effect on pol beta primarily by distorting nucleotide binding or by directly affecting the catalytic step [Pelletier, H., Sawaya, M. R., Wolfle, W., Wilson, S. H., & Kraut, J. (1996b) Biochemistry 35, 12762-12777]. Crystal soaking experiments with 31-kDa apoenzyme crystals show that, in the absence of DNA, the HhH motif in the fingers subdomain binds metal ions with either much lower occupancy or not at all, indicating that metal ion binding is dependent on the presence of the DNA substrate.

ChemInform Abstract: Solvation and Complexation of Metals in Water‐Hydrogen Fluoride Mixtures. Sn, Cd, Pb, and Tl.

AbstractThe behavior of Sn and Tl in H2O‐HF mixtures (0‐100% HF) is studied polarographically.

Polarographic Behavior of Metal Ions in the Presence of Polyethylene Glycol in Potassium Chloride1

Abstract The polarographic behavior of Cu(II), Pb(II), Tl(I), Sn(II), In(III), Cd(II), and Zn(II) was investigated in the presence of polyethylene glycol (PEG) in 0.1 mol dm−3 potassium chloride. PEG was adsorbed on mercury drops within the potential range from ca.−0.2 through −1.50 V vs. SCE, and shifted the half-wave potentials of Sn(II), In(III), Cd(II), and Zn(II) toward the negative direction, leaving the wave heights unchanged. On the other hand, the polarograms of Cu(II), Pb(II), and Tl(I) were not affected by the presence of PEG. Linear relationships between the wave heights for Cu(II), Pb(II), In(III), Cd(II), Zn(II), and their concentrations were obtained in the presence of PEG. Among these ions, the polarographic waves of In(III) and Cd(II), whose reduction potentials are very close together, became well separated in the presence of PEG. It is, therefore, possible simultaneously determine In(III) and Cd(II) in this medium. Interference between In(II) and Pb(II) was observed in freshly prepared solutions. It is, however, feasible to precisely determine both ions by using PEG as a reduction potential-shift reagent for In(III) in order to eliminate the interference.

The Polarographic Behavior of Tl(I) and Na(I) Ions and Bis(o-phenylenediamine)nickel(II) in N,N-Dimethylformamide- Dimethyl Sulfoxide Mixtures

Abstract The polarographic behavior of Tl(I) and Na(I) ions and the bis(o-phenylenediamine)nickel(II) [Ni(opd)2] complex were studied using N,N-dimethylformamide (DMF)–dimethyl sulfoxide (DMSO) mixed solvents of various compositions. The diffusion currents of the Tl(I) and Na(I) ions and [Ni(opd)2] complex decreased linearly with an increase in the concentration of the supporting electrolyte in DMF–DMSO solvent mixtures. The ratio of the slope to the intercept is related to the D coefficient in the revised Jones-Dole equation of viscosity. Ion-solvent interaction was considered from the Stokes radius, calculated from the diffusion current at an infinite dilution of the supporting electrolyte. The half-wave potentials of both the Tl(I) ion and the [Ni(opd)2] complex shifted to a negative direction with an increase in the concentration of the supporting electrolyte. Although the half-wave potential of the [Ni(opd)2] complex shifted to a slightly positive potential, that of the Tl(I) ion shifted to a negative potential with an increase in the content of DMSO.

Quasilocal impurity states in Pb1-xSnxTe and PbSe0.08Te0.92 liquid-phase epitaxial layers doped with group-III elements.

The doping properties of Ga, In, and Tl-doped PbTe, ${\mathrm{Pb}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Sn}}_{\mathrm{x}}$Te, and ${\mathrm{PbSe}}_{0.08}$${\mathrm{Te}}_{0.92}$ liquid-phase epitaxial layers were systematically studied as a function of impurity concentration, tin mole fraction, and temperature. The dependence of carrier concentration on impurity concentration was fitted to a model which assumes two doubly degenerate states per impurity atom, using the band parameters of the host material calculated according to the six-band model. From this fit the impurity-state energy and its dependence on temperature and x were obtained. The Ga and In impurity states lie deep within the conduction band, while that of Tl lies deep within the valence band, which explains the strong donor behavior of Ga and In and strong acceptor behavior of Tl. The impurity-state energy decreases linearly with increasing x. The temperature dependence of the In state could explain the anomalous temperature dependence of ${R}_{H}$ observed for ${\mathrm{Pb}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Sn}}_{\mathrm{x}}$Te heavily doped with In.

Voltammetry in fused acetamide

The voltammetric behavior of Pb(II), Cd(II), Tl(I) and Ni(II) in fused acetamide at 87°Chas been studied. The measurements have been carried out using normal polarography and cyclic voltammetry either with mercury or platinum electrodes. Only Tl(I) reduction occurs reversibly while all the other cations show some degree of irreversibility.

Voltammetry in fused acetamide

The voltammetric behavior of Pb(II), Cd(II), Tl(I) and Ni(II) in fused acetamide at 87°Chas been studied. The measurements have been carried out using normal polarography and cyclic voltammetry either with mercury or platinum electrodes. Only Tl(I) reduction occurs reversibly while all the other cations show some degree of irreversibility.

Extraction Behavior of Zinc(II), Cadmium(II), Mercury(II), Indium(III), and Thallium(III) as Thiocyanates in High-Molecular-Weight Amines and Some Mutual Binary Separations

Abstract The extraction behavior of Zn(II), Cd(II), Hg(II), In(III), and Tl(III) has been studied at different NH4CNS molarities in some commercially available liquid anion exchangers. The effect of such variables as the type of amine, molarity of NH4CNS, and pH of aqueous phase and organic diluent on extraction has been explored to achieve the best conditions of some mutual binary separations of analytical and radiochemical interest.

Study of the Behavior of Sb(III) and Tl(III) in Micro- and Macroconcentrations by Centrifugation

Study of the Behavior of Sb(III) and Tl(III) in Micro- and Macroconcentrations by Centrifugation

Separation of Mercury(II) as Chloride from Zinc(II), Cadmium(II), Gold(III), and Thallium(III) by Extraction in High-Molecular-Weight Amines

Abstract The extraction behavior of Zn(II), Cd(II), Hg(II), Au(III), and Tl(III) has been studied at different HCl molarities in some commercially available liquid anion exchangers. The effect of such variables as the type of amine, molarity of HCl, amine concentration, and organic diluent on extraction has been explored to suggest the best conditions of separation of Hg(II) from Zn(II), Cd(II), Au(III), and Tl(III).

General trends in the behavior of Cd, Hg, Tl and Bi in some major rock forming processes

Neutron activation data on Cd, Hg, Tl and Bi in 45 samples of abundant magmatic, sedimentary and metamorphic rocks and rock composites (consisting of a total of more than 200 samples) are reported. American standard rocks are included. On the base of literature values and the data of the present publication one arrives at the following average abundances for magmatic rocks in the upper continental crust: 110 ppb Cd, 30 ppb Hg, 970 ppb Tl, 60 ppb Bi and for sedimentary rocks: 260 ppb Cd, 330 ppb Hg, 830 ppb Tl, 375 ppb Bi. Abundance ratios for sedimentary to magmatic rocks are: 12 for Hg, 6 for Bi and 2·4 for Cd; the relative accumulation of the three elements in the sedimentary environment is assumed to be due to the degassing of the earth (excess volatile elements). In a thermal gradient of regional metamorphism from sedimentary to lower amphibolite facies a decrease of Hg, Bi and Cd from sedimentary abundances down to the range of “magmatic” abundances has been observed.

Aromatic Bromination by the Use of Organic and Inorganic Thallium Salts

Abstract Using organic and inorganic Tl salts, the following aromatic brominations were carried out in a CCl4 or HOAc solvent and were found to occur very smoothly; (A) aromatic bromination with TlBr3·4H2O, (B) aromatic bromination with Br2 in the presence of Tl(III) and Tl(I) salts, and (C) the bromination of arylthallium(III) compounds. From a study of the relative rates and selectivities of benzene and toluene, it was deduced that an arylthallium(III) compound was not involved as an intermediate in the A and B reactions, that Tl(III) salts were more effective catalysts than Tl(I) salts for the B bromination, and that the A reaction was essentially identical with the B reaction with the TlBr3·4H2O catalyst. By considering the difference in the catalytic behavior of Tl(III) and Tl(I) salts in the B reaction, probable mechanisms are suggested.