Zinc Thallium Research Articles

On the origin of the high Kerr coefficient measured in thallium–zinc–tellurite glasses

Measurements of Kerr electrooptical sensitivity of several zinc–thallium–tellurite glasses are presented, and composition dependence of Kerr sensitivity is compared with the dependence of the second harmonic generation efficiency collected for optically poled TeO2–TlO0.5–ZnO glasses. These data being analyzed jointly with Raman measurements data allowed us to conclude that the high electrooptical Kerr coefficient and nonlinearity of Tl2O–ZnO–TeO2 glasses, and their sharp increase with augmenting concentration of thallium oxide TlO0.5 above 15% should be attributed to the presence of Tl+ cations having very high non-linear polarizability most likely related to their electronic lone pairs.

Fluorescence line narrowing spectroscopy of Eu 3+ in zinc–thallium–tellurite glass

The environment of Eu 3+ in zinc–thallium–tellurite glass of the molar composition 60TeO 2–30TlO 0.5–9.9ZnO–0.1Eu 2O 3 was investigated by laser-induced fluorescence line narrowing (FLN) techniques using Eu 3+ as a local site probe. From the site selective luminescence spectra of Eu 3+ at 7 K, the energies of the Stark components of the 7 F 1 and 7 F 2 states were recorded and then the crystal field parameters B nm were calculated assuming a C 2 v site symmetry. The ratios B 22/ B 20 and B 44/ B 40 for each excitation energy within 7 F 0– 5 D 0 transition were obtained and compared with the values calculated for Eu 3+ in other types of glasses.

A novel tetrachlorothallate (III)–PVC membrane sensor for the potentiometric determination of thallium (III)

A novel tetrachlorothallate (III) (TCT)-selective membrane sensor consisting of tetrachlorothallate (III)–2,3,5-triphenyl-2-H-tetrazolium ion pair dispersed in a PVC matrix plasticized with dioctylphthalate is described. The electrode shows a stable, near-Nernstian response for 1×10 −3–4×10 −6 M thallium (III) at 25 °C with an anionic slope of 56.5±0.5 over the pH range 3–6. The lower detection limit and the response time are 2×10 −6 M and 30–60 s, respectively. Selectivity coefficients for Tl(III) relative to a number of interfering substances were investigated. There is negligible interference from many cations and anions; however, iodide and bromide are significantly interfere. The determination of 0.5–200 μg ml −1 of Tl(III) in aqueous solutions shows an average recovery of 99.0% and a mean relative standard deviation of 1.4% at 50.0 μg ml −1. The direct determination of Tl(III) in spiked wastewater gave results that compare favorably with those obtained by the atomic absorption spectrometric method. The electrode was successfully applied for the determination of thallium in zinc concentrate. Also the tetrachlorothallate electrode has been utilized as an end point indicator electrode for the determination of thallium using potentiometric titration.

Spectrophotometric determination of thallium in zinc and zinc-base alloys with iodoacetic acid and hexamethylenetetramine.

Thallium(III) forms a ternary complex of yellow colour with iodoacetic acid and organic bases, especially hexamethylenetetramine. The complex is soluble in water and various organic solvents. Zinc, copper, cadmium and iron do not form complexes with these reagents, so that a spectrophotometric determination of thallium in zinc and its alloys is possible. The limit of detection is 15 microg g(-1), the molar absorption coefficient about 2000 mol(-1) l(-1) cm(-1).

Determination of traces of thallium in zinc and cadmium metals and process solutions by atomic-absorption spectrophotometry after extraction with di-isopropyl ether and reductive stripping

The bromo-complex of thallium(III) is extracted into di-isopropyl ether and reductively stripped into sodium sulphite solution, which is then analysed for thallium by atomic-absorption spectrophotometry. Thallium in zinc and cadmium metals and process solutions can be determined by this method.

Electronic Absorption Spectrum of Ni2+ Ions Doped in Zinc Thallium Sulphate Hexahydrate

AbstractOptical absorption spectra of Ni2+ ions doped in zinc thallium sulphate hexahydrate (ZT1SH) are studied at room and liquid nitrogen temperatures. The spectrum shows characteristic features of Ni2+ ions in octahedral crystalline fields. At liquid nitrogen temperature, one of the bands exhibits splitting. The fine splitting is interpreted as due to spin‐orbit interaction. From a detailed analysis of the bands of the spectrum, the crystal field parameters B, C, Dq, and ξ are evaluated.

Determination of thallium in zinc by proton activation analysis

The determination of thallium in unalloyed zinc by proton activation analysis, based on the 203Tl (p,3n) 201Pb reaction, is described. Lead-201 was radiochemically separated from the matrix activities (gallium, copper and zinc) by cation exchange, anodic deposition of lead (IV) oxide and precipitation as lead thionalide. Thallium (III) oxide was used as the standard. The method was applied to the BCR reference materials 321,322,323,324 and 325 Unalloyed Zinc. The detection limit is 17 ng g −1. The relative standard deviation obtainable is 5-1% in the 1-40 μg g −1 concentration range.

Absorption Spectrum of Mn2+ Ions Doped in Zinc Thallium Sulphate Hexahydrate

Abstract The optical absorption spectrum of Mn2+ ions doped in zinc thallium sulphate hexahydrate has been studied at room and liquid nitrogen temperatures. The observed bands are assigned as transitions from the 6A1g(S) ground state to various excited quartet levels of Mn2+ ion in octahedral symmetry. The fine structure observed in the 4T2g(D) band is explained as due to spin-orbit interaction. All the observed band positions have been fitted with the parameters B, C, Dq and α .

Absorption spectrum of Co 2+ ions doped in zinc thallium sulphate hexahydrate

The optical absorption spectrum of Co 2+ ions doped in zinc thallium sulphate hexahydrate has been studied at room and liquid nitrogen temperatures. The crystal shows characteristic absorption of Co 2+ ion in the visible and near infrared regions. The observed bands are assigned as transitions from the ground state 4T 1g(F) to various excited quartet and doublet levels of the Co 2+ ion in octahedral symmetry. The splitting in one of the bands at liquid nitrogen temperature has been explained to be due to spin-orbit splitting. All the observed band positions have been fitted with the parameters B, C, Dq and ξ.

Determination of traces of thallium in zinc and zinc-base alloys

A method is described for the determination of thallium at 5 p.p.m. level in zinc and zinc-base alloys. Thallium is extracted as an ion pair of its bromo complex and crystal violet into isopropyl ether and the absorbance is measured at 595 nm.

Spectrophotometric Determination of Thallium in Zinc and Cadmium with Rhodamine B

Spectrophotometric Determination of Thallium in Zinc and Cadmium with Rhodamine B

Zn:Tl PHASE DIAGRAM AT VERY LOW THALLIUM CONCENTRATIONS

The Zn:Tl liquidus has been accurately determined from pure Zn (419.505 °C) to the monotectic transition temperature (416.926 °C at 0.42 at.% Tl) using precision resistance thermometry. The upper solidus was determined approximately from measurements of the distribution coefficient (~0.01) and the solid solubility limit (~0.004 at.% Tl) of thallium in zinc. A value 1.53 ± 0.1 kcal/mole for the latent heat of fusion of pure zinc was calculated from the freezing point depressions.