The gravimetric determination of thallium(i) as thallium(i) tetraphenylboron

A gravimetric method for the determination of thallium(I) as thallium(I) tetraphenylboron has been developed. The method compares favorably with the classical chromate method. The effect of acid concentration and interference by other metal ions was studied as well as the thermal stability of the precipitate.     

Extraction separation of thallium (III) from thallium (I) with n-octylaniline

A novel method is developed for the extraction separation of thallium(III) from salicylate medium with n-octylaniline dissolved in toluene as an extractant. The optimum conditions have been determined by making a critical study of weak acid concentration, extractant concentration, period of equilibration and effect of solvent on the equilibria. The thallium (III) from the pregnant organic phase is stripped with acetate buffer solution (pH 4.7) and determined complexometrically with EDTA. The method affords the sequential separation of thallium(III) from thallium(I) and also commonly associated metal ions such as Al(III), Ga(III), In(III), Fe(III), Bi(III), Sb(III) and Pb(II). It is used for analysis of synthetic mixtures of associated metal ions and alloys. The method is highly selective, simple and reproducible. The reaction takes place at room temperature and requires 15-20 min for extraction and determination of thallium(III).     

(Chloromethyl)thallium(III) compounds

Aryl(chloromethyl)thallium chlorides, Ar(ClCH₂)TlCl (Ar=C₆H₅, p-CH₃C₆H₄) have been prepared by treatment of arylthallium dichlorides with diazomethane. The derived carboxylates, Ar(ClCH₂)TlX, react with HgX₂ to give the dicarboxylates, (ClCH₂)TlX₂ (X = OCOCH₃, OCOC₃H₇-i) and with tetramethyltin to give CH₃(ClCH₂)TlX compounds. R(ClCH₂)TIX compounds (R = CH₃, C₆H₅, p-CH₃C₆H₄) undergo disproportionation in methanol to R₂TlX and (ClCH₂)₂TlX compounds.     

Synthesis and Structure of Tris(8-mercaptoquinolinato)thallium and Tris(8-hydroxyquinolinato)thallium Monohydrate

Tris(8-mercaptoquinolinato)thallium Tl(C₉H₆NS)₃ and tris(8-hydroxyquinolinato)thallium monohydrate Tl(C₉H₆NO)₃·H₂O have been synthesized. Their structures have been confirmed by X-ray crystallographic analysis.     

Bis(B-carboranyl)thallium salts

Conclusions Borothallated carboranylthallium bis(trifluoroacetates) are converted to bis(B-carboranyl)thallium salts by treatment with AcONa or LiAlH₄.Translated from Izvestiya Akademii Nauk SSSR, Serlya Khimicheskaya, No. 6, pp. 1426–1428, June, 1981.     

Cerimetric determination of thallium (I)

Summary The cerimetric determination of thallium(I) has been reinvestigated. A new procedure for the potentiometric titration of thallium(I) with ceric sulphate at the room temperature and at a low concentration of hydrochloric acid (1.0 N) has been developed using iodine monochloride as catalyst.The authors wish to express their grateful thanks to the Ministry of Education, Government of India, for the award of a Research Scholarship and the authorities of the Andhra University for providing research facilities.     

Tetrachloroaurate(III) oxidation of thallium(I)

Summary The complementary reaction between Tl^I and AuCl _inf4 ^sup– was studied in a 3.0 mol dm^–3 HCl medium. The active species of oxidant and reductant were found to be HAuCl₄ and TlCl _inf2 ^sup– , respectively. A mechanism involving these reactive species is proposed, in agreement with the results obtained.     

Sequential oxidimetric determination of thallium(I) and (III)

The reaction between thallium(III) and oxalic acid in sulphuric acid medium has been investigated. Spectrophotometric results show that thallium(III) can be quantitatively reduced to thallium(I) with oxalic acid in aqueous medium when heated to near boiling point. Conditions for the estimation of the excess of oxalic acid with cerium(IV) sulphate in the presence of thallium(I) and for the estimation of a mixture of thallium(I) and thallium(III) have been investigated. The method is simpler than many other redox methods reported for the determination of thallium(III) and is free from many interferences encountered in these titrations. The reagents are cheap and quite stable.     

Dichrometric determination of thallium (I)

Summary A dichrometric procedure has now been developed for the direct volumetric titration of thallium(I), to an iodine monochloride end point. The concentration of the hydrochloric acid must be at least 7.5 N at the end point.     

Dichromate titration of thallium(I)

The formal redox potentials of the thallium(III)-thallium(I) couple in different acids of varying strengths are reported. The minimum concentration of hydrochloric acid required for a direct titration of thallium(I) with potassium dichromate is 5M. Thallium(I) can be titrated directly with the primary standard oxidant, potassium dichromate, at room temperature, with ferroin as indicator, in 6M hydrochloric acid. Atmospheric oxygen must be excluded.     

Trimethylsilylmethyl derivatives of thallium(III)

Some trimethylsilylmethyl derivatives of thallium(III) have higher stability and unusual coordination behavior in comparison with simple alkylthallim(III) analogs for steric reasons.     

Radiation induced exchange reaction between thallium(I) and thallium(III)—Comparison of sulfuric acid and perchiloric acid solution

The rate constant of radiation induced exchange reaction between thallium(I) and thallium(III) ions has been studied for elucidating the mechanisms which are responsible for (T1(II) intermediates or bridging groups (SO ₄ ^2– ) in sulfuric acid and perchloric acid solutions. It was found that the radiation induced exchange reaction is accelerated by the sulfate ion, and the rate of the thallium(II)-thallium(I) reaction is faster than that of the thallium(II)-thallium(III) process in perchloric acid solution.     

A [205T1]-thallium NMR study of thallium(I) and thallium(III) fluorometalates in acetonitrile

The concentration-dependent behavior observed for ²⁰⁵T1 n.m.r. resonances from thallium(I) fluorometalates, PF₆^-, WF₇^-, MoF₆^- and UF₆^-, in acetonitrile indicates that some degree of ion-pairing is present in these solutions. The paramagnetic anion, UF₆^-, has a pronounced effect on ²⁰⁵T1 resonance in the T1⁺ salt, but its effect on T1³⁺ is very small. It is suggested that T1³⁺ is effectively solvated by MeCN and that direct ion-pairing is unimportant. The ²⁰⁵T1 shielding of T1³⁺ is decreased by the presence of T1⁺ in solution, possibly as a result of the increase in asymmetry of the T1³⁺ environment.     

Aggregation behaviour of thallium(I) beta-diketiminates

Modulation of the steric requirements of a number of N-aryl beta-diketiminate ligands results in the isolation of a variety of Tl(I) compounds with different stabilities and nuclearities.