Determination of rare earths and thorium in apatites by thermal and epithermal neutron-activation analysis

A procedure is described for the non-destructive determination of Na, Mn, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu and Th in apatites by thermal and epithermal neutron-activation of independent portions of the material. The method was applied to three apatites with different contents. The precision obtained was better than +/-5% for La, Ce, Sm, Eu, Gd, Tb and Dy and +/-20% for Yb, Nd, Ho, Er and Lu for an apatite with a total rare-earth oxide content of the order of 1%. Determination of Ce, Tb and Yb could only be carried out with thermal neutron-activation analysis, while Gd, Ho and Er could only be determined after irradiation with epithermal neutrons.     

用非等温DSC曲线确定Ln(NCS)3-·4C3H5CH2NH2的热分解反应机理函数及热分解反应动力学参数

本文利用非等温DSC曲线对十二种镧系元素异硫氰酸盐与苄胺形成的配合物Ln(NCS)3·4C6H5CH2NH2(Ln=La、Pr、Nd、Sm、Eu、Ge、Tb、Dy、Ho、Er、Tm、Yb)进行了非等温动力学研究, 并运用积分法和微分法进行了分析, 推断了它们的热分解反应机理函数。     

Coordination polymers based on inorganic lanthanide(II) sulfate skeletons and an organic isonicotinate N-oxide connector: segregation into three structural types by the lanthanide contraction effect

Fourteen three-dimensional coordination polymers of general formula [Ln(lNO)(H2O)(SO4)]n, where Ln = La, 1.La; Ce, 2.Ce; Pr, 3.Pr; Nd, 4.Nd; Sm, 5.Sm; Eu, 6.Eu; Gd, 7.Gd; Tb, 8.Tb; Dy, 9.Dy; Ho, 10.Ho; Er. 11.Er; Tm, 12.Tm; Yb, 13.Yb; and Lu, 14.Lu; INO = isonicotinate-N-oxide, have been synthesized by hydrothermal reactions of Ln3+, MnCO3, MnSO4 x H2O, and isonicotinic acid N-oxide (HINO) at 155 degrees C and characterized by single-crystal X-ray diffraction, IR, thermal analysis, luminescence spectroscopy, and the magnetic measurement. The structures are formed by connection of layer, chain, or dimer of Ln-SO4 by the organic connector, INO. They belong to three structural types that are governed exclusively by the size of the ions: type I for the large ions, La, Ce, and Pr; type II for the medium ions, Nd, Sm, Eu, Gd, and Tb; and type III for the small ions, Dy, Ho, Er, Tm, Yb, and Lu. Type I consists of two-dimensional undulate Ln-sulfate layers pillared by INO to form a three-dimensional network. Type II has a 2-fold interpenetration of "3D herringbone" networks, in which the catenation is sustained by extensive pi-pi interactions and O-H...O and C-H...O hydrogen bonds. Type III comprises one-dimensional chains that are connected by INO bridges, resulting in an alpha-Po network. The progressive structural change is due to the metal coordination number decreasing from nine for the large ions via eight to seven for the small ions, demonstrating clearly the effect of lanthanide contraction. The sulfate ion acts as a micro4- or micro3-bridge, connecting two, three, or four metals, and is both mono- and bidentate. The INO ligand acts as a micro3- or micro2-bridge with carboxylate group in syn-syn bridging or bidentate chelating mode. The materials show considerably high thermal stability. The magnetic properties of 4.Nd, 6.Eu, 7.Gd, and 13.Yb and the luminescence properties of 6.Eu and 8.Tb are also investigated.     

交流电弧中共存稀土元素对光谱线强度影响的研究

本工作较系统地研究了在交流电弧中不同量的共存稀土元素镝、钬，饵，铥和镱对某些被测稀土元素光谱线强度的影响。用交流电弧激发溶液干渣样品，其样品是在固定量的被测元素溶液中各自分别加入不同量的共存元素镝、钬、铒、铥和镱，摄谱后测量各被测元素的光谱线强度对共存元素在溶液中各个不同浓度作关系曲线。     

The 7-Iodo-8-Quinolinol-5-Sulfonic Acid Chelates of Some Rare Earth Metal Ions

The dissociation constants of 7-iodo-8-quinolinol-5-sulfonic acid and the formation constants of it's chelates with La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III) and Lu(III) have been determined potentiometrically in 1:1 v/v dioxane-water medium at 25±0.1°C and at an ionic strength of 1 with respect to sodium chloride.     

Chemical Bond Parameters in Sr_3MRhO_6(M=Rare earth)

over tile years, tile collcept of bolld covalellcy or ionicity has been proved to be a veryilllpol'tallt quantity in classifyillg and explaining many basic properties of molecules andsolids from the viewpoint of the electronic structure. Nevertheless, previous study in thisaspect was only on binary crystals, which limited the usefulness of the theory. Therecently proposed method I for the evaluation of chemical bond parameters includingbond covalency has made the study on crystals with multipl…     

Tetrafluoroaurate(III) der Lanthaniden M2F[AuF4]5 (M = Tb,Dy, Ho,Er)

Tetrafluoroaurates(III) of Lanthanoides M₂F[AuF₄]₅ (M = Tb, Dy, Ho, Er) Tetrafluoroaurates(III) M₂F[AuF₄]₅ with M = Tb, Dy, Ho, Er, all yellow, have been obtained. From single crystal data they crystallize triclinic, space group P1 -C¹_i (No. 2) with Tb: a = 1 194,34(7) pm, b = 798,46(6) pm, c = 902,02(7) pm, α = 89,033(7)°, β = 88,990(6)°, γ = 89,006(7)°; Dy: a = 1 191,66(9) pm, b = 796,33(8) pm, c = 899,65(9) pm, α = 88,956(8)°, β = 89,056(8)°, γ = 88,972(8)°; Ho: a = 1 189,06(10) pm, b = 795,46(6) pm, c = 896,81(7) pm, α = 88,912(8)°, β = 89,101(7)°, γ = 88,873(8)°; Er: a = 1 185,20(40), b = 793,98(14), c = 893,83(20), α = 88,751(23)°, β = 89,187(26)°, γ = 88,884(9)°     

Hydrothermal Synthesis of Rare Earth Iodates from the Corresponding Periodates: II1). Synthesis and Structures of Ln(IO3)3 (Ln = Pr,Nd, Sm,Eu, Gd,Tb, Ho,Er) and Ln(IO3)3 · 2H2O (Ln = Eu,Gd, Dy,Er, Tm,Yb)

Single crystals of lanthanide iodates have been quickly grown by decomposition of the corresponding periodates under hydrothermal conditions. Single crystal X‐ray diffraction showed that two structure types form with the elements from Pr‐Yb, an anhydrous form for Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er and a dihydrate for Eu, Gd, Dy, Er, Tm, Yb. A detailed structure study is presented for one representative of each of these types, along with structure type and lattice parameters for the other materials. Tb(IO₃)₃: Space group P2₁/c, Z = 4, lattice dimensions at 120 K: a = 7.102(1), b = 8.468(1), c = 13.355(2)Å, β = 99.67(1)°; R1 = 0.034. Yb(IO₃)₃ · 2H₂O: Space group P1¯, Z = 2, lattice dimensions at 120 K: a = 7.013(1), b = 7.370(1), c = 10.458(2)Å, α = 95.250(5), β = 105.096(5), γ = 109.910(10)°; R1 = 0.024.     

Application of atomic absorption spectrophotometry for the determination of lanthanides in ores and rare earth concentrates

Summary Concentrations of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Y were determined in rare earth ores and concentrates by the flame atomic absorption method, those of Eu, Gd, Dy, Ho, Er, Tm, Yb and Y also by the flameless method with a graphite cell. Accuracy was checked by using a standard lanthanides mixture. The results of the determinations in concentrates (by flame and by furnace AAS, both direct measurement and standard addition method) were compared with those obtained by spectrophotometry. Detection limits were defined in a HGA-70 graphite cell with application of a standard graphite tube. The results of the examinations revealed that both the AAS methods are suitable for lanthanide determinations in the above materials. Heavy lanthanides can be determined in lower concentrations than by spectrophotometry.

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Anwendung der Atomabsorptions-Spektralphotometrie zur Bestimmung von Lanthaniden in Erzen und Seltenerd-Konzentraten

Zusammenfassung La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb und Y wurden in Erzen und Konzentraten mit Hilfe der Flammen-Atomabsorptionsspektrometrie bestimmt, Eu, Gd, Dy, Ho, Er, Tm, Yb und Y auch nach der flammenlosen Methode unter Anwendung der Graphitküvette. Die Genauigkeit wurde mit Hilfe einer Standardmischung von Lanthaniden geprüft. Die Ergebnisse der Bestimmungen in Konzentraten (Flammen- und flammenlose AAS, Direktmessung und Methode der Standardzugaben) wurden mit spektralphotometrischen Resultaten verglichen. Die Nachweisgrenzen wurden für die Graphitküvette HGA-70 mit Standardgraphitröhre bestimmt. Es ergab sich, daß beide AAS-Methoden für den genannten Zweck verwendbar sind. Die schweren Lanthanide können in niedrigeren Konzentrationen bestimmt werden als mit Hilfe der Spektralphotometrie.

     

邻氯苯甲酸稀土配合物的合成、表征及结构

本文合成了邻氯苯甲酸与十五种稀土的配合物REL~3·H~2O(RE=Y,La～Lu,L=Clc~6H~4CO~2H),研究了它们的热分解及红外光谱.测定了钕、铽及镥三种稀土的配合物晶体结构,均属单斜晶系,空间群P2~1/n,稀土离子配位数为9,配合物呈无限链状聚合结构.     

A family of rare-earth-based single chain magnets: playing with anisotropy

The first family of rare-earth-based single chain magnets is presented. Compounds of general formula [M(hfac)3(NITPhOPh)], where M = Eu, Gd, Tb, Dy, Ho, Er, or Yb, and PhOPh is the nitronyl-nitroxide radical (2,4'-benzoxo-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), have been structurally characterized and found to be isostructural. The characterization of both static and dynamic magnetic properties of the whole family is reported. Dy, Tb, and Ho compounds display slow relaxation of the magnetization, and ac susceptibility shows a thermally activated regime with energy barriers of 69, 45, and 34 K for Dy, Tb, and Ho compounds, respectively, while only a frequency-dependent susceptibility is observed for Er below 2.0 K. In Gd and Yb derivatives, antiferromagnetic interactions dominate. The pre-exponential factors differ by about 4 orders of magnitude. Finite size effects, due to naturally occurring defects, affect the static and dynamic properties of the compounds differently.     

An XRF method for the determination of common rare earth impurities in high purity yttrium oxide

Summary An XRF method for the determination of Eu, Gd, Tb, Dy, Ho, Er and Yb in yttrium oxide has been developed. The samples are converted to yttrium oxalate and presented to the spectrometer in the form of pressed pellets. Philips PW-1220, semiautomatic X-ray spectrometer is used for analysis. Analysis lines have been chosen after careful study of line interferences. The lower estimation limit for Yb is 0.01% and for other elements it is 0.005%. The method has been tested for its accuracy by analysing synthetic samples with known composition.

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Bestimmung von häufig vorkommenden Verunreinigungen an Seltenen Erden in Yttriumoxid hoher Reinheit mit Hilfe der Röntgenfluorescenzanalyse

Zusammenfassung Ein Verfahren zur röntgenfluorescenzanalytischen Bestimmung von Eu, Gd, Tb, Dy, Ho, Er und Yb in Yttriumoxid wurde ausgearbeitet. Die Probe wird zu Yttriumoxalat umgesetzt und in Form von Preßtabletten der RFA unterworfen. Das halbautomatische Röntgenfluorescenz-Spektrometer Philips PW-1220 wurde verwendet. Eine sorgfältige Untersuchung der Interferenzen führte zur Wahl der Analysenlinien. Die untere Bestimmungsgrenze liegt für Yb bei 0,01%, für die anderen Elemente bei 0,005%. Die Zuverlässigkeit des Verfahrens wurde anhand von synthetischen Proben bekannter Zusammensetzung geprüft.

     

1,5-双(1'-苯基-3'-甲基-5'-吡唑啉酮-4')-戊二酮-[1,5]和十六烷基吡啶盐的稀土配合物的合成及表征

合成了13种1,5-双(1′-苯基-3′-甲基-5′-吡唑啉酮-4′)-戊二酮-[1,5](BPMPPD)和溴化十六烷基吡啶盐(CPB)的稀土配合物.研究了配合物的红外光谱、紫外可见光谱、差热-热重谱、荧光光谱、核磁共振谱及摩尔电导等性质,发现配合物属离子型缔合物CP⁺[Ln(BPMPPD)₂]^-.Pr、Nd、Ho、Er、Tm配合物发生超灵敏跃迁.配合物的热分解温度具有"四分组"效应,Sm、Eu、Tb、Oy为线性荧光。     

Synthesis and single-crystal x-ray diffraction examination of a structurally homologous series of tetracoordinate heteroleptic anionic lanthanide complexes: Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(L)3 (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb; (L)3 =(THF)3, (Et2O)3, (THF)2(Et2O)

Anhydrous lanthanide(III) chlorides (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) react with 3 equiv of lithium 2,2,5,5-tetramethyl-2,5-disila-1-azacyclopentanide, Li[N[Si(CH3)2CH2Ch2Si(CH3)2]], in THF or Et(2)O to afford the monomeric four-coordinate heteroleptic ate complexes Ln[N[Si(CH3)2CH2CH2Si(CH3)2]]3(mu-Cl)Li(THF/Et2O)3 (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Tm (8), Yb (9)), whose solid-state structures were determined by the single-crystal X-ray diffraction technique. All complexes additionally were characterized by melting point determination, elemental analyses, and mass spectrometry.     

Molar enthalpies of formation of LnAl2 compounds

The enthalpy of solution of Eu in Al and the standard molar enthalpy of formation of LnAl₂ (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) were determined by dissolution calorimetry, using a calorimeter based on liquid aluminium. Experimental results are compared with model predictions.     

Fluoroplatinate(IV) der Lanthaniden LnF[PtF6]. (Ln = Pr,Sm, Gd,Tb, Dy,Ho, Er)

Fluoroplatinates(IV) of the Lanthanides LnF[PtF₆] (Ln = Pr, Sm, Gd, Tb, Dy, Ho, Er) For the first time fluorides LnF[PtF₆] (Ln = Pr, Sm, Gd, Tb, Dy, Ho, Er), all yellow have been obtained. From single crystal data they crystallize monoclinic, space group P2₁/n?C (No. 14), Z = 4, Pr: a = 1 125.77(19) pm, b = 559.04(7) pm, c = 910.27(17) pm, β = 107.29(1)°; Sm: a = 1 114.63(31) pm, b = 552.70(12) pm, c = 898.02(20) pm, β = 107.24(2)°; Gd: a = 1 112.12(15) pm, b = 551.22(7) pm, c = 891.99(11) pm, β = 107.09(1)°; Tb (Powder data): a = 1 108.88(20) pm, b = 552.71(9) pm, c = 889.56(16) pm, β = 107.30(1)°; Dy: a = 1 100.28(23) pm, b = 547.77(8) pm, c = 882.41(13) pm, β = 107.32(1); Ho: a = 1 099.11(16) pm, b = 546.16(7) pm, c = 879.45(15) pm, β = 107.34(1)°; Er: a = 1 095.10(16) pm, b = 544.82(10) pm, c = 874.85(14) pm, β = 107.37(1)°.     

Determination of dissociation constants for some pyrogallol azo derivatives and stability constants of their complexes with rare-earth metals

The dissociation constants of some haloazo derivatives of pyrogallol and the stability constants of their complexes with rare-earth metals (La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) are determined by potentiometric titration in aqueous ethanol (3: 7). A correlation between the dissociation constants of the reagents and the stability constants of their complexes is found.     

Synthesis,characterization and thermal behaviour of solid 2-methoxybenzoates of trivalent metals

Solid-state Ln(L)₃ compounds, where Ln stands for trivalent Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and L is 2-methoxybenzoate have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results provided information on the composition, dehydration, coordination mode, structure, thermal behaviour and thermal decomposition.     

Effect of ionic liquids on the extraction of rare-earth elements by bidentate neutral organophosphorus compounds from chloride solutions

The partition of microamounts of lanthanide chlorides (Ln = La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y) between aqueous HCl and organic solutions of tetraphenylmethylenediphosphine dioxide, diphenyl(diethylcarbamoylmethyl)phosphine oxide, and dibutyl(diethylcarbamoylmethyl)phosphine oxide was studied in the presence of ionic liquids (ILs): 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The stoichiometry of extracted complexes was determined. The effect of the aqueous HCl concentration, the nature of the extractant, and the organic diluent on the efficiency of lanthanide extraction was studied.     

乙酰丙酮-5,10,15,20-四-(对氯苯基)卟啉稀土配合物的制备和性质

用丙酸做溶剂,吡咯与对氯笨甲醛反应制备5,10,15,20-四-(对氯苯基)卟啉(p-Cl)Tpp;后者与稀土乙酰丙酮配合物Ln(acac)₃·3H₂O在1,2,4-三氯苯中反应制得乙酰丙酮-5,10,15,20-四-(对氯苯基)卟啉稀土配合物Ln(p-Cl)Tppacac;并做了元素分析、UV、IR和PMR等性质的研究。