共查询到20条相似文献,搜索用时 31 毫秒
1.
Thermolysis curves for scandium, yttrium, lanthanum, cerium(III), neodymium, samarium, gadolinium, dysprosium and erbium diliturates are described, Scandium diliturate forms a 15-hydrate which dehydrates in 3 steps. The other diliturates all form 12-hydrates which dehydrate smoothly. All of the anhydrous diliturates are thermally stable to about 240°.Solubilities in water for scandium, yttrium, lanthanum, cerium(lll), neodymium, samarium. gadolinium, dysprosium and erbium diliturates are given. Scandium diliturate is the most soluble and neodymium diliturate the least soluble. Solubilities of rare earth diliturates not investigated can be predicted approximately.Methods for thermogravimetric determination of yttrium, lanthanum, neodymium, samarium, gadolinium, dyprosium, and erbium as the diliturates have been developed. The precipitates are quite dense, easily handled and filterable. Weighing as the diliturate salts gives these determinations a very favorable gravimetric factor. 相似文献
2.
D. E. Chirkst O. L. Lobacheva I. V. Berlinskii 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(12):2047-2050
The pH values of the formation of hydrates in solutions of yttrium(III), cerium(III), samarium(III), europium(III), erbium(III),
and ytterbium(III) were determined by conductometric titration. The solubility products and Gibbs energies of formation for
hydroxides for the elements listed were calculated. The average Gibbs energy of dissolution for lanthanide hydroxides was
found to be approximately 149.83 ± 0.90 kJ/mol. The Gibbs energies of formation for hydroxides of the remaining lanthanides
were assessed on this basis. 相似文献
3.
The thermolosis curves of the neocupferron chelates of yttnum, lanthanum, cerium(III), cerium(IV). praseodymium, neodymium, samarium and gadolinuim were determined. It was found that the ehelates were stable up to 8o°, with the oxide levels being reached at 460–750°. 相似文献
4.
The technique of pyrohydrolysis has been applied to the determination of fluorine in the fluorides of scandium, yttrium, and the lanthanons. These fluorides have been divided into two classes according to their rate of hydrolysis. Lutetium, ytterbium, cerium(III), scandium, gadolinium, terbium, dysprosium, holmium, erbium, and thulium florides can be hydrolyzed in 30 min or less. Yttrium, lanthanum, praseodymium, neodymium, samarium, and europium fluorides require from 45 to 150 min for complete hydrolysis. Accelerators, such as uranium oxide (U3O8), chromium(III) oxide, and a mixture of these oxides have been used successfully to reduce the tune required for quantitative hydrolysis of the fluorides in the latter group. The use of the correct accelerator reduces the hydrolysis time to 30 min or less for all these fluorides except lanthanum, praseodymium and neodymium. 相似文献
5.
Adsorption of selected ions on hydrous cerium oxide 总被引:2,自引:0,他引:2
A. Nilchi M. Yaftian G. Aboulhasanlo S. Rasouli Garmarodi 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):65-74
Hydrous cerium oxide was synthesized and laboratory study was conducted to address its applicability for decontamination of
barium, strontium, molybdenum, europium, iodine, samarium and cesium ions from radioactive liquid wastes using radiotracer
technique. The adsorption of Ba(II), Sr(II), Mo(II), Eu(II), I(I), Sm(III) and Cs(I) on hydrous cerium oxide has been investigated
as a function of pH, concentration and temperature of the adsorptive solution and the result obtained show that these parameters
affect the extent of adsorption. The ion-exchange capacity decreased at higher temperatures which could be due to decrease
of active sites as well as hydrophilic properties of surface adsorbent. Hydrous cerium oxide shows relatively high adsorption
in acidic and neutral media towards the radiotracers studied, which can be attributed to large hydrated radius and ion exclusion
effect. 相似文献
6.
Lanthanum, cerium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium and yttrium have been determined in 8 international rock standards by inductively coupled plasma atomic emission spectrometry (ICP-AES) without prior ion-exchange separation and preconcentration. The results for La, Ce, Nd, Eu, Dy, Yb and Y were in good agreement with the reported values, whereas those for Sm, Gd, Er and Lu were less accurate. However, the results for Sm, Gd, Er and Lu can also be used for studies of petrogenesis. 相似文献
7.
Natalia N. Vlasova Galina Yu. Zhila Anatoly I. Kirillov Mikhail G. Voronkov 《Heteroatom Chemistry》1995,6(4):311-312
Polymers of silsesquioxane structure, poly[bis-(3-silsesquioxanyl-propylamino)]sulfoxide ( IV ) and -sulfone ( V ) have been prepared and examined as complexation agents toward samarium(III) and thulium(III). Polymer IV was an effective complexation agent toward both of these elements. However, polymer V was an effective complexation agent only toward thulium(III) ions. The selective complexation of polymer V with thulium is not affected by the presence of excess amounts of lanthanum, cerium, neodymium, or samarium salt. This suggests that polymer V may prove to be useful in rare-earth element (REE) separation and isolation. The selective complexation of V with thulium(III) is also observed in the presence of nickel(II), copper(II), or lead(II) salt. 相似文献
8.
为了准确测定板栗中矿物元素和稀土元素的含量水平,采用冷冻干燥方式预处理样品,选用硝酸和过氧化氢体系微波消解样品,结合电感耦合等离子体质谱技术,建立了板栗中钠(Na)、钾(K)、镁(Mg)、锰(Mn)、铁(Fe)、钒(V)、钴(Co)等19种矿物元素及镧(La)、铈(Ce)、镨(Pr)、钕(Nd)、钐(Sm)、铕(Eu)、钆(Gd)、铽(Tb)、镝(Dy)、钬(Ho)、铒(Er)、铥(Tm)、镱(Yb)、镥(Lu)、钇(Y)等15种稀土元素的同时分析测定方法。方法检出限为0.0027~0.78μg/L,相对标准偏差为1.4%~6.3%。通过国家标准物质GBW10019苹果的准确度实验验证,测定结果均在标准证书值范围内。实验结果表明,方法适用于板栗中矿物元素及稀土元素的同时测定。 相似文献
9.
D. E. Chirkst O. L. Lobacheva I. V. Berlinskii M. A. Sulimova 《Russian Journal of Applied Chemistry》2009,82(8):1370-1374
Experimental dependences of the distribution coefficients of cerium(III) and yttrium(III) dodecyl sulfates on the pH value
of the equilibrium aqueous phase in the course of ion flotation are reported. Conditions for separation of cerium(III) and
yttrium(III) are discussed. A value of the dissociation constant found from experimental results of potentiometric titration
of dodecylsulfuric acid with sodium hydroxide is presented. 相似文献
10.
Gaber A. Elinany Fikry M. Ebeid Ahmed M. Zahra Farouk I. Ziedan 《Journal of Electroanalytical Chemistry》1976,72(3):363-369
The polarographic behavior of metal ions in perchlorate media containing gallic acid is described. Tungsten(VI) forms a complex with gallic acid which yields a single wave in these media, useful in the polarographic determination of tungsten. Evidence for complexation of chromium(III), copper(II), iron(III), molybdenum(VI), uranium(VI), vanadium(V), tungsten(VI), praseodymium(III), samarium(III), neodymium(III) and gadolinium(III) is obtained and the behavior of these metal ions is summarized. 相似文献
11.
R. A. Cherkasov A. R. Garifzyanov R. R. Galeev N. V. Kurnosova R. R. Davletshin S. V. Zakharov 《Russian Journal of General Chemistry》2011,81(7):1464-1469
The processes of membrane transport of ions of scandium(III), samarium(III), gadolinium(III), neodymium(III), aluminum(III),
and a number of alkali and alkaline earth metals through liquid membrane impregnated with aminophosphoryl carriers of different
structures were studied. Selectivity of bis (dialkylphosphinyl)amines towards scandium was found to be significantly higher
than the selectivity of diphosphinylpiperazine and monophosphinylamine in particular. The dependence of transfer efficiency
on the concentration of substrates and carriers was revealed. Optimal conditions for transporting rare and trace metal ions
through the membrane were found, and the mechanism of transmembrane transport was discussed. 相似文献
12.
D. E. Chirkst O. L. Lobacheva I. V. Berlinskii N. V. Dzhevaga 《Russian Journal of Applied Chemistry》2011,84(2):341-344
The ionic flotation of cerium(III) and samarium(III) from nitrate solutions with sodium dodecylsulfate as a collector and sodium chloride addition was studied. Dependences of distribution coefficients and a separation factor on the aqueous phase pH at various concentrations of chloride ions were determined. 相似文献
13.
Vasudevan KV Smith NA Scott BL McKigney EA Blair MW Gordon JC Muenchausen RE 《Inorganic chemistry》2011,50(10):4627-4631
A novel synthetic route to a series of cerium bromide solvates is reported. The combination of bulk cerium bromide and the ionic liquid (IL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide results in a precursor paste that enhances the solubility of the cerium(III)bromide moiety in a number of donor solvents. Crystallization from these solvents has resulted in the isolation and characterization of CeBr(3)(THF)(4) (2), CeBr(3)(2-Me-THF)(4) (3), and CeBr(3)(MeCN)(5)·MeCN (4). Additionally, 2 is shown to be an efficient precursor for the new species CeBr(3)(py)(4) (5) and CeBr(3)(bipy)(py)(3) (6). 相似文献
14.
A method is described for the extractive separation and spectrophotometric determination of uranium(VI) from an aqueous solution of pH 5.0–7.0 using benzoylacetone (bzac) and pyridine (py) dissolved in toluene as extractants. The extracted species are UO2(bzac(2·2py. The method provides separation of uranium(VI) from lanthanum(III), samarium(III), neodymium(III), cerium(III) and thorium(IV). The method is precise, accurate, fast and selective. 相似文献
15.
16.
Abbasi A Risberg ED Eriksson L Mink J Persson I Sandström M Sidorov YV Skripkin MY Ullström AS 《Inorganic chemistry》2007,46(19):7731-7741
The octakis(DMSO) (DMSO = dimethylsulfoxide) neodymium(III), samarium(III), gadolinium(III), dysprosium(III), erbium(III), and lutetium(III) iodides crystallize in the monoclinic space group P21/n (No. 14) with Z = 4, while the octakis(DMSO) iodides of the larger lanthanum(III), cerium(III), and praseodymium(III) ions crystallize in the orthorhombic space group Pbca (No. 61), Z = 8. In all [Ln(OS(Me2)8]I3 compounds the lanthanoid(III) ions coordinate eight DMSO oxygen atoms in a distorted square antiprism. Up to three of the DMSO ligands were found to be disordered and were described by two alternative configurations related by a twist around the metal-oxygen (Ln-O) bond. To resolve the atomic positions and achieve reliable Ln-O bond distances, complete semirigid DMSO molecules with restrained geometry and partial occupancy were refined for the alternative sites. This disorder model was also applied on previously collected data for the monoclinic octakis(DMSO)yttrium(III) iodide. At ambient temperature, the eight Ln-O bond distances are distributed over a range of about 0.1 A. The average value increases from Ln-O 2.30, 2.34, 2.34, 2.36, 2.38, 2.40 to 2.43 A (Ln = Lu, Er, Y, Dy, Gd, Sm, and Nd) for the monoclinic [Ln(OSMe2)8]I3 structures, and from 2.44, 2.47 to 2.49 A (Ln = Pr, Ce, and La) for the orthorhombic structures, respectively. The average of the La-O and Nd-O bond distances remained unchanged at 100 K, 2.49 and 2.43 A, respectively. Despite longer bond distances and larger Ln-O-S angles, the cell volumes are smaller for the orthorhombic structures (Ln = Pr, Ce, and La) than for the monoclinic structure with Ln = Nd, showing a more efficient packing arrangement. Raman and IR absorption spectra for the [Ln(OS(CH3)2)8]I3 (Ln = La, Ce, Pr, Nd, Gd, Tb, Dy, Er, Lu, and Y) compounds, also deuterated for La and Y, have been recorded and analyzed by means of normal coordinate methods. The force constants for the Ln-O and S-O stretching modes in the complexes increase with decreasing Ln-O bond distance and show increasing polarization of the bonds for the smaller and heavier lanthanoid(III) ions. 相似文献
17.
Summary Separation and determination of lanthanum, cerium, praseodymium, neodymium and samarium in monazites have been achieved by
dynamic ion-exchange chromatography. The ore samples are decomposed by sulfuric acid and the rare earths are separated in
a group as oxalates. The rare earth elements are then separated from each other on a column of bonded phase silica by gradient
elution with 0.05 to 0.5 M lactic acid (pH 3.5) in the presence of 0.01 M sodium 1-octanesulfonate. Post-column reaction with
Arsenazo III is used for detection and quantification of the individual rare earth elements. Results are quoted for lanthanum,
cerium, praseodymium, neodymium and samarium in monazites. Detection limit is 1 μg ml−1 with a S/N ratio of 3. The separation is complete within 27 min valley to valley resolution. Precision of better than 1%
can usually be obtained. 相似文献
18.
G. L. Nealon M. Mocerino M. I. Ogden B. W. Skelton 《Journal of inclusion phenomena and macrocyclic chemistry》2009,65(1-2):25-30
The syntheses of samarium, holmium, and ytterbium complexes of a tris-amide calix[4]arene are described, and the resulting structures are compared with the previously reported gadolinium complex. The syntheses involved the reaction of 5,11,17,23-tetra-tert-butyl-24-hydroxy-26,27,28-tris(diethylcarbamoylmethoxy)calix[4]arene with the appropriate lanthanide picrate hydrate. Structural studies demonstrated that a picrate anion acts as a quasi-bidentate ligand with Sm (and Gd), is unidentate in the Ho complex, but is found in the second coordination sphere for the smallest lanthanide cation (Yb) investigated. 相似文献
19.
A method is proposed for determination of lanthanum, cerium, praseodymium, neodymium, and samarium in mineral water by means of total-reflection X-ray fluorescence analysis. In this work, the combined technique of preconcentration of rare earth ions is used. This technique consists of coprecipitation of metal hydroxides on the collector (iron (III) hydroxide) and dispersive liquid–liquid microextraction of their complexes with 1-(2-pyridylazo)-2-naphthol by chloroform in the presence of ethanol. The use of the developed hybrid approach allows simultaneous determination of the mentioned metals in mineral water in the range n(10–2–101) μg/L. The results of analysis of Arkhyz and Rychal-Su mineral waters by the proposed extraction–X-ray fluorescent method are confirmed by the literature data, obtained by inductively coupled plasma mass spectrometry. 相似文献
20.
A very sensitive method for the spectrophotometric determination of manganese is reported. To the sample is added triethanolamine (TEA) and sodium hydroxide to give a pH above 11; after atmospheric oxidation of manganese(II) to the green manganese(III)—TEA complex, sodium pyrophosphate is added and the solution is acidified. Manganese(III) thus forms a complex with pyrophosphate. Then o-tolidine is added and is oxidized in a 2e step to the intensely yellow quinonediimine, while manganese(III) is reduced to manganese(II). The absorbance is measured at 440 nm. The calibration curve is linear up to 1.6 μg Mn ml-1 in the final solution; the limit of determination is 0.2 μg Mn ml-1. For the 20-cm path cell, the respective data are 45 ng Mn ml-1 and 2 ng Mn ml-1. The only severe interferences are strong oxidants like dichromate or cerium(IV), which are readily reduced with sulfurous acid. Vanadium in amounts up to 2–3 times that of manganese can be dealt with by an appropriate blank solution; larger amounts of vanadium must be removed e.g. by a cupferron extraction. 相似文献