Ceric Solution Research Articles

A critical study of the standardization of cerium(IV) solutions against arsenic trioxide

The standardization of cerium(IV) solutions against arsenic trioxide is critically reviewed. If a gravimetric titration with spectrophotometric determination of the excess of cerium(IV) is used, an accuracy of 0.01% can be achieved. The directional difference ( ca. 0.03%) in direct and reverse titrations observed in the standardization ofcerium(IV) solutions against arsenic trioxide is caused by a reaction between water and cerium(IV). The use of iodide ion as catalyst, instead of osmium tetroxide, is described.

The use of the ceric arsenious acid reaction for the determination of small amounts of iodine or iodine compounds

Some aspects of the ceric arsenious acid reaction were studied. Attention was paid to the optical properties of ceric solutions. Also the consequences of the mathematical model of the reaction in relation to spectrophotometric measurements are discussed. At last the kinetic effects of several compounds were studied, more especially the effects of chloride and bromide ions and the kinetic effects of chloride or bromide in combination with iodide.

Kinetic and analytical studies on the oxidation of methanol and ethanol by ammonium hexanitratocerate(IV)

A detailed study of the kinetics of the oxidation of methanol with ammonium hexanitratocerate(IV) has shown interesting features which differ from the kinetics of the oxidation with cerium (IV) perchlorate. The different features are discussed in terms of the species of cerium(IV) occurring in solutions of cerium(IV) in nitric acid and perchloric acid. Improved procedures have been developed for the determination of methanol and ethanol with cerium(IV) nitrate.

Separation of molybdenum from several interfering elements by tribenzy lamine extraction of its thiocyanate

A simple extraction of molybdenum for routine analysis is proposed. Molybdenum(VI) is reduced with hydrazine sulphate in 2 M hydrochloric acid. Fluoride is added to mask various metal ions, and the Mo(V)-thiocyanate complex is extracted by 1% tribenzylamine in chloroform. Molybdenum is back-extracted with an alkaline hydrogen peroxide solution. After suitable treatment, milligram amounts of molybdenum are determined by titration with cerium(IV) solution, and microgram amounts by spectrophotometry of the thiocyanate complex. The separation requires only about 20 min (< 10 min in series operation) and separates molybdenum from Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Nb, W, Ce, Bi, U, Ru, Pb and Sb. The wide applicability of the method is shown by satisfactory analysis of a variety of synthetic samples for molybdenum.

Complex formation of lanthanum(III) or cerium(III) with 3-aminomethylalizarin-n.n-diacetic acid and fluoride

The complex formation in aqueous solution of lanthanum(III) or cerium(III) with 3-aminomethylalizarin-N,N-diacetic acid (alizarin complexan, L) and fluoride (F) was studied by spectrophotometry. At pH 4.50 the metals react with alizarin complexan to form the compounds LaL or CeL; the conditional constant of LaL is 3.6·10 4. At pH 5.50 and 6.50 both systems contained a mixture of the 1:1 species with complexes containing two or more metal ions per ligand molecule. The ternary metal-alizarin complexan-fluoride systems were studied by recording absorption and continuous variations curves, and plotting theoretical curves of continuous variations for various ML-fluoride complexes. The results showed that the ternary complexes have the composition (ML) 2F 2, the conditional constant at pH 4.50 being 6.3·10 13 for the lanthanum complex. It is shown theoretically that ternary complexes of the form (ML) 2F 2 and (ML)F are characterized by having continuous variations curves with maxima displaced to higher mole fractions of the binary reactant. The differences between the curves for the two types are discussed. The ternary complex probably consists of a ring-formed dimer La 2L 2 with one fluorine atom attached to each of the two metal atoms.

A new spot test for cerium(IV) using triphenylmethane dyes

A new sensitive and selective spot test for cerium(IV) using the triphenylmethane dyes, Erioglaucine A, Eriogreen B, Xylenecyanol FF, Setoglaucine O, and Setocyanine Supra, respectively, is described. The method consists of adding one drop of the dye solution (0.1%) to a drop of cerium(IV) solution, and then treating the mixture with sufficient amount of sulfuric, perchloric, or phosphoric acid to maintain the acidity at 6 to 9M. The colors produced with these dyes are: Erioglaucine A: orange, Eriogreen B: bright red, Xylenecyanol FF: orange yellow, Setoglaucine O: bright orange, and Setocyanine Supra: pink. The identification limit is 1 μg in 1.5 ml, and the dilution limit is 1∶1.5 · 106 in all these cases. Many cations and anions do not interfere in the test, whereas reducing agents like Fe(II), Mo(V), U(IV), and hydroquinone, fluoride and EDTA interfere.

Variables in the standardization of ceric solutions against arsenious oxide

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVariables in the standardization of ceric solutions against arsenious oxideR. C. Schlitt and Keith. SimpsonCite this: Anal. Chem. 1969, 41, 13, 1722–1726Publication Date (Print):November 1, 1969Publication History Published online1 May 2002Published inissue 1 November 1969https://doi.org/10.1021/ac60282a020RIGHTS & PERMISSIONSArticle Views171Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (618 KB) Get e-Alerts Get e-Alerts

Ceric ion equilibrium in aqueous acetic acid

Ceric ion equilibrium in aqueous acetic acid

Superconductivity, Low-Temperature Resistivity, and Thermoelectric Power of Dilute Solid Solution of Ce in In and Sn

An interesting anomalous property of cerium metal is that its valence is not fixed, being able to be in a trivalent (magnetic) or in a tetravalent (nonmagnetic) state. It has been suggested that this, as well as the other anomalous properties of cerium, are due to the fact that the f-electrons are on external orbits, thus being able to interact with the conduction electrons in a similar manner to the d-electrons of the transition metals. If the f-electrons are not tightly bound in cerium metal, the possibility exists that dilute solid solutions of cerium in nontransition metals could induce the similar electron transport anomalies as transition metal impurities. We have measured the superconducting critical temperature Tc of In-Ce and Sn-Ce solid solutions as a function of the impurity concentration, as well as the resistivity and the thermoelectric power down to 0.3°K. An approximately linear decrease of Tc has been observed in both alloy systems up to the solid solubility limit (150 ppm at.). For In-Ce ΔTc/ρ is −8°K and for Sn-Ce ΔTc/ρ is −20°K, where ρ is the residual resistance ratio R4.2/ (R273−R4.2) which varies linearly with concentration (c) and has the values of ρ/c = 0.31/at.% for the In-Ce system and ρ/c = 0.0471/at.% for the Sn-Ce system. The values of ΔTc/ρ are larger than would be expected on the basis of normal impurity scattering; however, the resistivity and thermoelectric power measurements do not indicate the presence of localized magnetic moments, the former showing no minimum and the latter being positive and small (S ≈ 0.3 mV/°K) for the present temperature range of measurements. We believe that if the assumption is made that a virtual f-level lies near the Fermi energy, the observed magnitude of the suppression of the superconducting critical temperature as well as the small positive thermopowers could be explained on the basis of existing theories.

Dosage du plutonium par potentiometrie a intensite constante: Application au combustible de rapsodie

A new method is proposed for the determination of plutonium in the UO 2PuO 2 pellets for Rapsodie. The sample is dissolved in a mixture of II N nitric acid and 0.l N hydrofluoric acid, and the plutonium is oxidized with silver(II) oxide. Plutonium(VI) is reduced in the presence of sulphamic acid with an excess of iron(II) which is back-titrated with cerium(IV) solution to a constant-current potentiometric end-point. Uranium and iron do not interfere and no separation is required. In routine work, the method gives a precision of 0.5%.

Some measurements of the heat of solution of cerium in liquid tin using a liquid-metal solution calorimeter

A calorimeter intended for the determination of heats of formation of alloy phases by measuring heats of solution in liquid metals is described. The characteristics of the apparatus are discussed and its satisfactory performance is established by the redetermination of the heat of solution of pure solid silver in liquid tin at 828°K; a value of +3674 (mean deviation ±16) cal (g atom)-1 Ag was observed. Using a variety of specimens, measurements have been made of the heat of solution of solid (face-centred cubic) cerium in liquid tin at 634°K. Highly exothermic behaviour was observed, with a mean value of -68 400 (mean deviation ±730) cal (g atom)-1 Ce being obtained.

The microdetermination of hydrazino functional groups in boron hydride compounds

Summary Hydrazine and azide functional groups can be determined in the presence of boranes by a modified microgasometric procedure. Hydrazine groups are oxidized to nitrogen with an iodate solution and azides are converted to nitrogen by the use of a ceric solution. The evolved gases are passed through a heated zone of copper oxide in a stream of carbon dioxide, and the hydrogen evolved by the borane is coverted to water. The nitrogen evolved is collected and measured in an azotometer.

Complexometric titration of yttrium and the lanthanons—I: A comparison of direct methods

A comparison is made of a number of direct complexometric titrations previously published for the determination of yttrium and the lanthanons. Working and ‘optimum’ pH ranges are obtained for what are considered to be the best indicators. Alizarin Red S screened with Methylene Blue, Erioehrome Black T, Copper-Naphthyl Azoxine and Xylenol Orange. The precision and accuracy of the selected methods are determined by carrying out replicate titrations on standard solutions of cerium III, yttrium and ytterbium. The results, together with additional observations made on the behaviour of indicators in the different methods, suggest that Xylenol Orange at pH 5.8 to 6.4 is most satisfactory and convenient for direct titrations.

Cerimetrie en milieu nitrique. application au dosage du fer, de l'uranium et du plutonium

A method is described for titrimetric determination of iron, uranium or plutonium in nitric acid media. The element is reduced with titanium(III) solution in presence of sulfamic acid, and titrated with cerium(IV) solution. Precautions normally taken for nitric acid media are unnecessary. The method is rapid and precise and is readily applicable to determinations of plutonium or irradiated uranium.

Volumetric Determination of Uranium in the Presence of Niobium Utilizing a Bismuth Metal Reductor

The use of bismuth metal as a reducing agent during the determination of uranium in the presence of large amounts of niobium was studied. Other metals or metal amalgams reduce both uranium and niobium, prohibiting a simple volumetric deteimination. When a strongly acid solution bismuth metal, the uranium(VI) is quantitatively reduced formed and without encountering the problem of niobium hydrolysis. The uranium is determined indirectly by reaction with excess iron(III), producing iron(II) which is titrated with standard cerium(IV) solution. The end point with extraction of the cobalt--2-nitroso-1-naphthol complex into chloroform results in an accurate and reliable method of the titration is determined potentiometrically. Interferences were encountered with iron, molybdenum, vanadium, and tungsten in mixtures of uranium and niobium but not with nickel, zirconium, chromium, beryllium, copper, titanium, and aluminum.

The effect of heat on solutions of cerium(IV) sulphate in sulphuric acid and some analytical implications

Ceric sulphate solutions may undergo appreciable losses of cerium(IV) on heating. The overall loss is acid dependent, being at a minimum in about 1 M sulphuric acid, and is almost independent of the cerium(IV) concentration. Consequently as the concentration falls the actual percentage loss increases. The loss, resulting from the reaction of cerium(IV) with water, is catalysed heterogeneously at the glass surface and also on the surface of any precipitated material. The extent of the loss varies considerably with the conditions of the experiment. Solutions of ceric sulphate prepared from commercial grade cerium(IV) sulphate or ceria and from spectroscopically pure ceria, behave in the same fashion. The effect of added silver(I), copper(II), mercury(II) and phosphite ions in the cerium(IV)—water reaction is reported.

The effect of heat on solutions of cerium(iv) sulphate in sulphuric acid and some analytical implications

Ceric sulphate solutions may undergo appreciable losses of cerium(IV) on heating. The overall loss is acid dependent, being at a minimum in about i M sulphuric acid, and is almost independent of the cerium(IV) concentration. Consequently as the concentration falls the actual percentage loss increases. The loss, resulting from the reaction of cerium(IV) with water, is catalysed heterogeneously at the glass surface and also on the surface of any precipitated material. The extent of the loss varies considerably with the conditions of the experiment. Solutions of ceric sulphate prepared from commercial grade cerium(IV) sulphate or ceria and from spectroscopically pureceria, behave in the same fashion.The effect of added silver(I), copper(II), mercury(II) and phosphite ions in the cerium (IV)- water reaction is reported.

Electronic Transitions of Rare Earth Ions in the Infrared Region

The 2F7/2←2F5/2 transition of the cerous ion has been observed in solid solutions of cerium(III) fluoride in cadmium fluoride. The band center is at about 2250 cm—1, in good agreement with the free-ion value of 2253.0 cm—1. The crystal field splitting of the band appears to be enhanced by the effect of the interstitial fluoride ions which compensate for the excess positive charge of Ce3+ in Cd2+ positions. Addition of NaF, which eliminates the interstitial fluoride ions, decreases the splitting. Praseodymium and neodymium ions in CdF2 also showed absorption bands.

Dissolution of Nickel in Acid Ferric and Ceric Solutions

Dissolution rates of nickel cylinders rotated in acidified solutions of and have been measured. The rates are transport‐controlled, but the Ni surface becomes extremely rough, and first‐order constants are obtained only if a uniform degree of roughness is maintained during runs. The values of the rate constants then depend on the structure of the metal, e.g., whether it has been annealed, mechanically worked, etc.

Anion Exchange Studies of Beryllium (II), Cerium (IV), Thorium (IV) and Uranium(VI) Carbonate Complex Ions

The anion exchange behavior of macro amounts of Be, Ce, Th, and uranyl carbonate ions formed in ammonium carbonate solution and tracer amounts of cerium and thorium carbonate complex ions formed in potassium carbonate were studied. Distribution coefficients were measured with the Dowex 1, X-8'' anion exchanger of carbonate form. (C.J.G.)