Showing papers on "Uranyl published in 1968"
TL;DR: In this article, the ultraviolet spectrum of the aqueous uranyl ion in a perchlorate medium has been resolved into twelve Gaussian shaped absorption bands; this is a continuation of the band analysis for the visible spectrum.
109 citations
51 citations
TL;DR: In this article, the reduction of the uranyl cation at a mercury electrode in strongly acidic perchlorate media has been studied using mainly linear sweep voltammetry, and the experimental results support th assumption of coupled ECE-disproportionation mechanisms.
51 citations
48 citations
TL;DR: The crystal structure of sodium uranyl triperoxide nonahydrate, Na4[UO2(O2)3],9H2O, has been determined by single-crystal X-ray diffraction, by the heavy-atom method.
Abstract: The crystal structure of sodium uranyl triperoxide nonahydrate, Na4[UO2(O2)3],9H2O, has been determined by single-crystal X-ray diffraction, by the heavy-atom method. The main structural feature is the uranyl triperoxide anion consisting of three co-planar peroxide groups equatorially surrounding a linear uranyl group, in approximately D3h symmetry. The mean U–O(uranyl) distance is 1·86, the U–O(peroxide) is 2·28 and the peroxide O–O 1·5 A. The water molecules are co-ordinated in octahedra around the sodium atoms. The crystals are monoclinic, space group P21/c, a= 6·413, b= 17·292, c= 14·186 A, β= 98·52°. The i.r. and Raman spectra of this and some related compounds are reported, with tentative assignments.
47 citations
TL;DR: It is concluded that only average size and general shape of the molecules can be reliably estimated by negative staining.
36 citations
TL;DR: In this paper, the crystal structure of Dioxo-dinitratobis(triphenylarsineoxide) uranium(VI) has been determined by X-ray diffraction.
31 citations
TL;DR: Complexes of uranyl ion with benzoic, phenylacetic, phenoxy-acetic and thiomalic acids were studied by pH titration method at 31±0.1°C.
Abstract: Complexes of uranyl ion with benzoic, phenylacetic, phenoxy-acetic, thiomalic and itaconic acids were studied by pH titration method at 31±0.1°C. A 1 : 1 complex is formed in all the cases in the pH range 2.5–3.5 and their stability constants are reported.
26 citations
TL;DR: The uranyl complexes of EDTA have been studied by potentiometry ; stability constants of the 1:1 and 2:1 (metal to ligand) chelates have been determined, as well as the respective hydrolysis and polymerization constants.
26 citations
24 citations
TL;DR: In this paper, the near visible absorption and emission spectra (spectrophotometric) and infrared spectra were obtained for adducts of uranyl nitrate with a large variety of organophosphorus and organonitrogen ligands, with the object of providing a rationale for the spectra of these uranyl compounds.
TL;DR: In this article, the polarographic behavior of anhydrous and hydrated uranium(IV)- and uranyl compounds was investigated in propane-diol-1,2-carbonate and in N,N-dimethylacetamide.
TL;DR: In this article, the stability of various zirconium phosphates ranging from granular amorphous to very good crystalline material was investigated for samples autoclaved at high temperatures in aqueous media.
TL;DR: In this paper, an equation for the bending frequency (ν2) of the uranyl ion was applied to determine the UO bond distance in a range of compounds, including K3UO2F5, NaUO 2(C2H3O2)3 and K2UOO2O2.
01 Jan 1968
TL;DR: In this paper, the reduction of uranyl(VI) acetate with cadmium or zinc is recommended for the laboratory preparation of uranium(IV) acetates, and the non-stoichiometry of zinc double acetate is explained by correlating its crystal structure with that of uranium-IV acetate.
TL;DR: In this article, the effect of solvated alcohol on the spectrum of uranyl-TTA complex (UO2T2) is discussed, and the transformation from ethanol and methanol to the orthorhombic form on exposure to air is discussed.
TL;DR: In this article, the first stage is the dehydration of the uranyl(VI) formate monohydrate followed contracting-sphere kinetics with energy of 36·2 ± 1·0 kcal/mole.
Abstract: Initial experiments involving thermogravimetry and differential thermal analysis have established the stages in the decomposition of uranyl(VI) formate monohydrate and anhydrous uranium(IV) formate in either inert or oxidising atmospheres.Analysis of the gases evolved when anhydrous uranyl(VI) formate is heated in a vacuum at 280° indicates that the reaction is mainly represented by the equation: 3UO2(HCO2)2→ 2HCO2H + 4CO + H2O + 3α-UO3. A secondary reaction occurs to a small extent where a basic formate, [UO(OH)(HCO2)], is formed which subsequently decomposes to give a form of uranium trioxide.Studies on uranium(IV) formate at 280° have indicated that in vacuum the reaction is: 2U(HCO2)4→ 3HCO2H + 4CO + H2+ CO2+ 2UO2. In air the salt is subject to oxidation and the first stage is that where uranyl(VI) formate is produced.The dehydration of the uranyl(VI) formate monohydrate followed contracting-sphere kinetics with energy of activation 36·2 ± 1·0 kcal./mole. The decarboxylation of the uranyl(VI) formate follows a Prout–Tompkins equation with energy of activation 40·4 ± 1·0 kcal./mole. In the case of uranium(IV) formate, the reaction in inert conditions followed a linear law with an energy of activation 28·5 ± 1·0 kcal./mole.Mechanisms which may account for the behaviour are discussed.
TL;DR: In this paper, two approximate equations of KMO = KUO - 0·0100(ZM - ZU)2 and KOMO = KOUO − 0·0075(Zm-ZU) 2 were derived on the basis of the data already published.
TL;DR: In this article, the authors studied the thermal decomposition of uranyl(VI) oxalate as a function of temperature in the range 300-350° and found that in an inert atmosphere the reaction follows Prout-Tompkins kinetics with activation energy 62·4 ± 1·0 kcal/mole, and the final product is uranium dioxide.
Abstract: The kinetics of the thermal decomposition of uranyl(VI) oxalate have been studied as a function of temperature in the range 300–350°. In an inert atmosphere the reaction follows Prout-Tompkins kinetics with activation energy 62·4 ± 1·0 kcal./mole, and the final product is uranium dioxide. In the presence of air, the final product is amorphous trioxide. The reaction is then composed of two consecutive stages: (a) a reaction on the surface of the subgrain boundaries following Prout-Tompkins kinetics, and (b) a reaction involving isolated disc-like grains of reactant which follows an Avrami-Erofeev law with n= 2. The kinetic parameters for these last two stages are sensibly consistent with those found for the reaction in inert atmospheres.
TL;DR: In this article, the effect of the supporting electrolyte (alkali carbonates and perchlorates) on the polarographic reduction of uranyl peroxodicarbonato ion has been studied.
TL;DR: In this paper, the complexation of uranyl ion with fumaric and maleic acids was investigated by polarography and conductometry, and the dissociation constants obtained from the half-wave potential vs. pH plots were pK1=3.05 and pK2=4.55 for Fumaric acid and Pk1=1.90 and pk2=5.60 for maleic acid.