- Synthesis, characterization and thermal behaviour of solid 2-methoxybenzoates of trivalent metals
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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 scanni
- Siqueira,Carvalho,Ionashiro,Bannach,Rodrigues,Ionashiro
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- Synthesis, characterization and thermal behaviour of solid-state tartrates of heavy trivalent lanthanides and yttrium(III)
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Solid state Ln2-L3 compounds, where Ln stands for heavy trivalent lanthanides (terbium to lutetium) and yttrium, and L is tartrate [(C4H4O6)-2] have been synthesized. Simultaneous thermogra
- Ambrozini, B.,Dametto, P. R.,Ionashiro, M.
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- Vacancy mediated room temperature ferromagnetism in Co-doped Dy 2O3
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Nanoparticles of Co doped dysprosium oxide [Dy1.90Co 0.10O3] were prepared by co-precipitating the precursor salts in presence of air and argon gas. Crystallographic phase and substitution of Co-ion in Dy2O3 were confirmed by Rietveld analysis of the x-ray diffraction patterns. Magnetic susceptibility and magnetization as a function of temperature and magnetic field were measured by Faraday and Superconducting quantum inteference device (SQUID) magnetometers, which showed that the sample synthesized in the inert atmosphere is ferromagnetic at room temperature. But no such effect has been observed in the other sample. This observation confirmed that vacancy mediated ferromagnetism can be introduced in the Co-doped dysprosium oxide.
- Bandyopadhyay,Sutradhar,Sarkar,Deb,Chakrabarti
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- Synthesis, characterization and thermal behaviour of heavy lanthanide and yttrium pyruvates in the solid state
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Solid-state Ln-L compounds, where Ln stands for heavy trivalent lanthanides or yttrium (III) (Tb-Lu, Y) and where L is pyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), X-R
- Siqueira,De Carvalho,Rodrigues,Ionashiro,Bannach,Ionashiro
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- Synthesis, characterisation and thermal behaviour of solid stat compounds of 4-methylbenzylidenepyruvate with heavier trivalent lanthanides and yttrium(III)
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Solid state Ln-4-Me-BP compounds, where Ln stands for heavier trivalent lanthanides (gadolinium to lutetium) and yttrium(III) and 4-Me-BP is 4-methylbenzylidenepyruvate (CH3-C6H4-CH=CH-COCOO-), have been synthesized. Eleme
- Marques,Melios,Ionashiro
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- Stability, water exchange, and anion binding studies on lanthanide(III) complexes with a macrocyclic ligand based on 1.7-diaza-12-crown-4: Extremely fast water exchange on the Gd3+ complex
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The picolinate-derivative ligand based on the 1,7-diaza-12-crown-4 platform (bp12c4 2-) forms stable Ln3+ complexes with stability constants increasing from the early to the middle lanthanides, then being relatively constant for the
- Palinkas, Zoltan,Roca-Sabio, Adrian,Mato-lglesias, Marta,Esteban-Gomez, David,Platas-Iglesias, Carlos,De Blas, Andres,Rodriguez-Blas, Teresa,Toth, Eva
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- Thermodynamic properties of some lanthanide chlorides
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The heat capacities of the lanthanide chlorides NdCl2, SmCl2, EuCl2, DyCl2, TmCl2, YbCl2, DyCl3, YbCl3 and LuCl3 were measured at 10-320 K with an adiabatic microcalorimeter. Standard thermodynamic properties were calculated from the experimental results. The heat capacities of these chlorides are composed of the lattice heat capacity and an additional contribution caused by the thermal population of the low-lying Stark electronic levels (Schottky anomaly). The Schottky heat capacity was estimated as the difference between the experimental Cp values for the isostructural paramagnetic and diamagnetic chlorides. Experimental Schottky contributions were found to be in good agreement with those calculated for SmCl2, TmCl2 and YbCl3 via a general model of the main-term Stark splitting of the respective ions in the orthorhombic and monoclinic crystal fields.
- Tolmach,Gorbunov,Gavrichev,Iorish
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- Lanthanide(III) halides: Thermodynamic properties and their correlation with crystal structure
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Temperatures and enthalpies of phase transitions of 17 lanthanide(III) halides determined experimentally are reported. Correlations were made between temperature of fusion of lanthanide(III) halides, on the one hand, and enthalpy of fusion, on the other, versus atomic number of lanthanide. According to this classification, the lanthanide(III) halides split into groups, as also do the corresponding crystal structures. A correlation between the crystal structure of lanthanide(III) halides and their respective entropy of fusion (or entropy of fusion + entropy of solid-solid phase transition) was inferred from the aforementioned features. Fusion in those halides with hexagonal, UCl3-type and orthorhombic, PuBr3-type, structures entails an entropy of fusion change (or entropy of fusion + entropy of solid-solid phase transition change) by 50 ± 4 J mol-1 K-1. The homologous entropy change within the group of halides having the rhomboedric, FeCl3-type, structure, is smaller and equals 40 ± 4 J mol-1 K-1. Halides with monoclinic, AlCl3-type, crystal structure constitute a third group associated to an even smaller entropy change upon fusion, only 31 ± 4 J mol-1 K-1. The halides with lower entropies of fusion also have a lower S1300 K - S298 K indicating either a higher degree of order in the liquid or a higher entropy in the solid at room temperatures.
- Rycerz,Gaune-Escard
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- Synthesis, characterization and thermal behaviour of solid 4-methoxybenzoates of heavier trivalent lanthanides
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Solid-state Ln-4-MeO-Bz compounds, where Ln stands for trivalent Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and 4-MeO-Bz is 4-methoxybenzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scan
- Rodrigues, Emanuel C.,Siqueira, Adriano B.,Ionashiro, Elias Y.,Bannach, Gilbert,Ionashiro, Massao
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- 2-Methoxybenzylidenepyruvatewith heavier trivalent lanthanides and yttrium(III): Synthesis and characterization
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Solid-state Ln(2-MeO-BP) compounds, where Ln stands for trivalent Eu to Lu and Y(III) and 2-MeO-BP (which is 2-methoxybenzylidenepyruvate) have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanni
- Ionashiro,Bannach,Siqueira,De Carvalho,Rodrigues,Ionashiro
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- Investigating the formation and magnetic properties of the Dy0.75Fe1.25O3 orthoferrite prepared by sol-gel method
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In this paper, the Dy0.75Fe1.25O3 orthoferrite nanoparticles were synthesized successfully by sol-gel method. Dy0.75Fe1.25O3 orthoferrite nanoparticles are obtained by calcining the flakes
- Li, Jian-Jun,Cao, Jun-Gang
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- Acceptor doping of Ln2Ti2O7 (Ln = Dy, Ho, Yb) pyrochlores with divalent cations (Mg, Ca, Sr, Zn)
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New LANTIOX high-temperature conductors with the pyrochlore structure, (Ln1-xAx)2Ti2O7-δ (Ln = Dy, Ho, Yb; A = Ca, Mg, Zn; x = 0, 0.01, 0.02, 0.04, 0.07, 0.1), have been prepared at 1400-1600 °C usin
- Belov,Shlyakhtina,Stefanovich,Kolbanev,Belousov,Karyagina,Shcherbakova
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- Thermodynamic re-optimization of the DyCl3-KCl system
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The intermediate compounds, K3DyCl6, K2DyCl5 and KDy2Cl7, in the DyCl3-KCl system, are confirmed by X-ray powder diffraction method. With CALPHAD technology the phase diagram of the DyCl3-KCl system is re-optimized and calculated using ChemSage software. A set of thermodynamic functions has been optimized based on an interactive computer-assisted analysis. The calculated phase diagram and optimized thermodynamic parameters are thermodynamically self-consistent.
- Xing, Xianran,Dai, Shuyu,Zhu, Zhenqi,Tanaka, Toshihiro
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- Lanthanide contraction and pH value controlled structural change in a series of rare earth complexes with p-aminobenzoic acid
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A series of rare earth complexes with p-aminobenzoic acid (HL) have been synthesized: [RE2L6(H2O)2] n [RE=La (1), Ce(2), Pr(3), Sm(4), Eu(5), Tb(6), Dy(7), Er(9)] and [RE2L6(H2O)4]·2H 2O [RE=Tb(6′), Ho(8), Yb(10), Lu(11), Y(12)]. The crystal structures of 1, 2, 6, 6′, 7, 9 and 12 have been determined and the isomorphous relationships of the others have been identified. Their structures change from two-dimensional (2D) array (the coordination number of the metal ions is nine for 1 and eight for 2-7 and 9) to double-nuclear structure (the metal ions are eight-coordinated) for 6′, 8 and 10-12, as controlled by lanthanide contraction. The structural type has been found influenced by the pH value of the reaction mixtures.
- Sun, Hao-Ling,Ye, Chao-Hong,Wang, Xin-Yi,Li, Jun-Ran,Gao, Song,Yu, Kai-Bei
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- Synthesis, characterization and thermal studies on solid compounds of 2-chlorobenzylidenepyruvate of heavier trivalent lanthanides and yttrium(III)
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Solid-state compounds of general formula LnL3· nH 2O, where Ln represents heavier lanthanides and yttrium and L is 2-chlorobenzylidenepyruvate, have been synthesized. Chemical analysis, simultaneous thermogravimetry-differential anal
- Bannach,Schnitzler,Treu Filho,Utuni,Ionashiro
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- Stepwise chlorination-chemical vapor transport reaction for rare earth oxide mixtures Gd2O3-Tb4O7, Tb4O7-Dy2O3 and Dy2O3-Ho2O3
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Stepwise chlorination-chemical vapor transport (SC-CVT) reaction has been investigated for the rare earth oxide mixtures Gd2O3-Tb4O7, Tb4O7-Dy2O3 and Dy2O3-Ho2O3 mediated by vapor complexes LnAlnCl3n+3 (where Ln=rare earth elements). The results show selective deposition of lighter elements at higher temperatures. The separation factors are 5.84 for Gd/Tb, 3.72 for Tb/Dy and 3.13 for Ho/Dy when using CO as the CVT carrier gas. A combination of enhanced separation factor with reduced total transport yield is also observed for the Tb4O7-Dy2O3 system when using argon as the CVT carrier gas.
- Sun, Yan-Hui,Zhang, Li-Qing,Lei, Peng-Xiang,Wang, Zhi-Chang,Guo, Lei
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- Electrogenerated luminescence of chosen lanthanide complexes at stationary oxide-covered aluminium electrode
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The electrochemiluminescence (ECL) of aqueous solutions of Tb3+, Dy3+, and Eu3+ complexes having a variety of ligand groups was studied using an oxide-covered aluminium electrode. The ligand groups, under study, were the aromatic acids (salicylic, phthalic), the chelatic ligands (ethylenediamine dl(o-hydroxy-phenylacetic acid), EDDHA and ethylenediamine tetraacetic acid, EDTA), as well as Schiff bases: 1,10-disalicylidene-4,7-diaza-1,10-decyldiamine and 2-salicylideneamine-2-hydroxymethyl-1,3-propanediol. The results show that the generated emissions were mainly the result of energy transfer from the ligands to the metals. The best ECL properties were observed in the case of the complexes Tb(III)-EDDHA, Dy(III)-EDDHA, and Dy(III)-salicylic acid. In the ternary systems: Schiff base-Tb(III)-Eu(III) energy transfer to the emitting level of the Eu(III) ion was observed.
- Staninski, Krzysztof,Lis, Stefan
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- Phase diagram and electrical conductivity of the DyBr3-RbBr binary system
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Phase equilibrium in the DyBr 3 -RbBr binary system was established from differential scanning calorimetry measurements. This system exhibits three compounds, namely Rb 3 DyBr 6 , Rb 2 DyBr 5 , and RbDy 2 Br 7 , and two eutectics located at DyBr 3 molar
- Chojnacka, I.,Rycerz, L.,Berkani, M.,Gaune-Escard, M.
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p. 481 - 488
(2012/06/04)
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- Self-assembled light lanthanide oxalate architecture with controlled morphology, characterization, growing mechanism and optical property
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Flower-like Sm2(C2O4)3· 10H2O had been synthesized by a facile complex agent assisted precipitation method. The flower-like Sm2(C2O 4)3·10H2O was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, thermogravimetry- differential thermal analysis and photoluminescence. The possible growth mechanism of the flower-like Sm2(C2O4) 3·10H2O was proposed. To extend this method, other Ln2(C2O4)3·nH2O (Ln = Gd, Dy, Lu, Y) with different morphologies also had been prepared by adjusting different rare earth precursors. Further studies revealed that besides the reaction conditions and the additive amount of complex agents, the morphologies of the as-synthesised lanthanide oxalates were also determined by the rare earth ions. The Sm2(C2O4) 3·10H2O and Sm2O3 samples exhibited different photoluminescence spectra, which was relevant to Sm 3+ energy level structure of 4f electrons. The method may be applied in the synthesis of other lanthanide compounds, and the work could explore the potential optical materials.
- He, Hongmei,Zhang, Youjin,Zhu, Wei,Zheng, Ao
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p. 1546 - 1552
(2011/10/01)
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- Preparation and characterization of rare earth orthoborates, LnBO 3 (Ln = Tb, La, Pr, Nd, Sm, Eu, Gd, Dy, Y) and LaBO3:Gd, Tb, Eu by metathesis reaction: ESR of LaBO3:Gd and luminescence of LaBO3:Tb, Eu
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Lanthanide orthoborates of composition LnBO3 (Ln = Tb, La, Pr, Nd, Sm, Eu, Gd, Dy, Y) and LaBO3:Gd, Tb, Eu have been prepared by metathesis reaction. This method provides a convenient route for the synthesis of orthoborates and its solid solutions at low temperatures. Powder X-ray diffraction and FT-IR spectroscopy were used to characterize these borates. Rare earth borates, (LnBO3) are isomorphous with different forms of CaCO3 depending on the radius of rare earth ion. LaBO3, LaBO3:Gd, Tb, Eu, PrBO3, NdBO3 crystallized in aragonite structure, SmBO3 crystallized in H-form and TbBO 3, EuBO3, GdBO3, DyBO3, YBO 3 crystallized in vaterite structure. The structural analysis of TbBO3 was carried out. The morphology of these borates was obtained from Scanning electron microscopy. Spin-Hamiltonian parameters for Gd 3+ are deduced from room temperature electron spin resonance spectrum of LaBO3:Gd. The luminescence of LaBO3:Tb, Eu gave characteristics peaks corresponding to Tb3+, Eu3+ respectively.
- Velchuri, Radha,Kumar, B. Vijaya,Devi, V. Rama,Prasad,Prakash, D. Jaya,Vithal
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p. 1219 - 1226
(2011/07/09)
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- Lanthanide carbonates
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The crystal and molecular structures of the rare earth carbonates with the general formulae [C(NH2)]3 [Ln(CO3)4 (H2O)]·2H2O (where Ln = Pr3+,Nd 3+,Sm3+,Eu3+,Gd3+,Tb 3+)and [C(NH2)]3 [Ln(CO3) 4]·2H2O (where Ln = Y3+,Dy 3+,Ho3+,Er3+, Tm3+,Yb 3+,Lu3+) were determined. The crystals consist of monomeric [Ln(CO3)4 (H2O)] 5-or [Ln(CO3)4] 5-complex anions in which the carbonate ligands coordinate to the Ln3+ion in a bidentate manner. The spectroscopic (UV/Vis/NIR and IR) properties of the crystalline lanthanide carbonates, as well as their aqueous solutions, were determined. Correlation between the spectroscopic and the structural data enabled us to conclude that the [Ln(CO3)4 (OH)]6-and [Ln-(CO 3)4]5- species predominate in the light and heavy lanthanide solutions, respectively. The nature of the Ln-O interaction was also discussed. The experimental data, as well as the theoretical calculations, indicated that the Ln-O(CO3 2-) bond is more covalent than the Ln-O(OH2) bond. Moreover, the covalency degree is larger for the heavy lanthanide ions. Inspection of the NBO results revealed that the oxygen hybrids, with the approximate composition sp4, form strongly polarized bonds with the 6s6p5d4 hybrids of lutetium. 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
- Janicki, Rafal,Starynowicz, Przemyslaw,Mondry, Anna
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p. 3601 - 3616
(2011/10/11)
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- Comparison of covalency in the lanthanide chloride and nitrate complexes based on the adsorption data on zeolite y
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The changes of the distribution constants Kd of lanthanide chlorides in the system: zeolite Y (solid phase)-sodium chloride (aqueous phase) were investigated. The evident tetrad effect in the change of log Kd values within the lantha
- G?adysz-P?aska, Agnieszka,Majdan, Marek,Ferenc, Wies?awa,Sarzyński, Jan
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p. 469 - 474
(2012/03/22)
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- Synthesis, characterization and thermal behaviour of solid-state 3-methoxybenzoates of heavy trivalent lanthanides and yttrium(III)
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Solid-state Ln(L)3 compounds, where Ln stands for trivalent Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and L is 3-methoxybenzoate, have been synthesized. X-ray powder diffractometry, infrared spectroscopy, complexometry and elemental analysis were used to characterize the compounds. Inorder to study the thermal behaviour of these compounds simultaneous th ermogravimetry and differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC) were used. The results provided information on the composition, dehydration, polymorphic transformation, thermal stability and thermal decomposition of the synthesized compounds.
- Dametto, P. R.,Ambrozini, B.,Siqueira, A. B.,Carvalho, C. T.,Ionashiro, M.
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p. 933 - 940
(2011/01/06)
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- Structural characterization of methanol substituted lanthanum halides
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The first study into the alcohol solvation of lanthanum halide [LaX3] derivatives as a means to lower the processing temperature for the production of the LaBr3 scintillators was undertaken using methanol (MeOH). Initially the de-hydration of {[La(μ-Br)(H2O)7](Br)2}2 (1) was investigated through the simple room temperature dissolution of 1 in MeOH. The mixed solvate monomeric [La(H2O)7(MeOH)2](Br)3 (2) compound was isolated where the La metal center retains its original 9-coordination through the binding of two additional MeOH solvents but necessitates the transfer of the innersphere Br to the outersphere. In an attempt to in situ dry the reaction mixture of 1 in MeOH over CaH2, crystals of [Ca(MeOH)6](Br)2 (3) were isolated. Compound 1 dissolved in MeOH at reflux temperatures led to the isolation of an unusual arrangement identified as the salt derivative {[LaBr2.75·5.25(MeOH)]+0.25 [LaBr3.25·4.75(MeOH)]-0.25} (4). The fully substituted species was ultimately isolated through the dissolution of dried LaBr3 in MeOH forming the 8-coordinated [LaBr3(MeOH)5] (5) complex. It was determined that the concentration of the crystallization solution directed the structure isolated (4 concentrated; 5 dilute) The other LaX3 derivatives were isolated as [(MeOH)4(Cl)2La(μ-Cl)]2 (6) and [La(MeOH)9](I)3·MeOH (7). Beryllium Dome XRD analysis indicated that the bulk material for 5 appear to have multiple solvated species, 6 is consistent with the single crystal, and 7 was too broad to elucidate structural aspects. Multinuclear NMR (139La) indicated that these compounds do not retain their structure in MeOD. TGA/DTA data revealed that the de-solvation temperatures of the MeOH derivatives 4-6 were slightly higher in comparison to their hydrated counterparts.
- Boyle, Timothy J.,Ottley, Leigh Anna M.,Alam, Todd M.,Rodriguez, Mark A.,Yang, Pin,Mcintyre, Sarah K.
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p. 1784 - 1795
(2010/07/03)
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- Solubility behavior of rare earths with ammonium carbonate and ammonium carbonate plus ammonium hydroxide: Precipitation of their peroxicarbonates
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The purpose of this work is to report the significant behavior of the rare earths when treated with ammonium carbonate and with a binary mixture of ammonium carbonate plus ammonium hydroxide. The carbonates of some rare earths are completely soluble in ammonium carbonate or in ammonium carbonate plus ammonium hydroxide, while others are only partially soluble and finally some are completely insoluble. Addition of hydrogen peroxide to the soluble complexed rare earth carbonates results in the precipitation of a series of a new compounds described as rare earth peroxicarbonates. The rare earths have some different precipitation behavior in the carbonate-peroxide system. Some are completely and immediately precipitated, others are completely precipitated after an aging period, and finally other are not precipitated at all. These different behaviors open a new possibility for the separation chemistry of the rare earths. Sm, Gd, Dy, Y, Yb and Tm are fast and completely soluble in ammonium carbonate. Ho, Eu and Tb are completely soluble in ammonium carbonate but slowly dissolved. La, Ce, Pr and Nd are only partially soluble in ammonium carbonate. While Ce, Pr, Nd, Sm, Eu and Dy are completely and easily soluble in the ammonium carbonate plus ammonium hydroxide mixture, La is only partially soluble and Tb is completely insoluble in the same mixture. Concerning the peroxicarbonates, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy and Ho are quantitatively precipitated. The precipitation of the Er peroxicarbonate is quantitative, but after an aging period of 24 h. Y is not precipitated at all. The process is very easy, simple and economically attractive. Although proved in bench scale, its scale-up is easily feasible.
- de Vasconcellos, Mari E.,da Rocha,Pedreira,Queiroz, Carlos A. da S.,Abr?o, Alcídio
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p. 426 - 428
(2008/10/09)
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- Comparison of thermal properties of lanthanide trimellitates prepared by different methods
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By diffusion in gel medium new complexes of formulae: Nd(btc) ·6H2O, Gd(btc)·4.5H2O and Er(btc)?5H2O (where btc=(C6H3(COO)33-) were obtained. Isomorphous compounds were crystallized in the
- Lyszczek, Renata
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p. 833 - 838
(2009/02/07)
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- A systemic study of stepwise chlorination-chemical vapor transport characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by alkaline chlorides as complex former
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A systematic study has been carried out for the stepwise chlorination-chemical vapor transport (SC-CVT) characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by the vapor complexes KLnCl4 and NaLnCl4 (Ln = Sc, Y and La-Lu) used NaCl and KCl as complex former, respectively. The results showed that the SC-CVT characteristics are similarly for NaCl and KCl as complex former, the main deposition temperature of the rare earth chlorides LnCl3 is in the increasing order ScCl3 3 3, and then with a systematically decreasing trend from the early lanthanide chlorides to the end one. The results also showed that the total transported amount of the produced chlorides is YCl3 > ScCl3, and they are much higher than that of most lanthanoid chlorides. For lanthanoids, the total transported amount of chloride increases systematically from the early lanthanoid chlorides to the end one except for EuCl3 and GdCl3 mediated by KCl and NaCl as complex former, respectively, which showed the divergence effect of Gd in the total transport efficiency. But there are some differences in SC-CVT characteristics of pure rare earth oxide mediated by KCl and NaCl as complex former, that is the main deposition temperature region for the same rare earth element was lower for KCl than that for NaCl as complex former except for LaCl3, CeCl3, YbCl3 and LuCl3, while the total transport amount of rare earth chloride for KCl as complex former is higher than that for NaCl except for LaCl3 and EuCl3. More over, the discussion was carried out for Sc and Y on the one hand and the lanthanides contain 4f electron as another hand based on the 4f electron hybridization assumption. Further more, the transport characteristics of rare earth oxides with alkaline chlorides as complex former in this study were compared to that with AlCl3 as complex former.
- Sun, Yan-Hui,He, Peng,Chen, Hua-Ni
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p. 352 - 358
(2008/10/09)
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- Microcalorimetric studies on the interactions of lanthanide ions with bovine serum albumin
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The interactions of lanthanide ions (Ln3+) with bovine serum albumin (BSA) under mimetic physiological conditions (310.15 K, pH 6.7, 0.1MNaCl) were studied by microcalorimetry. For the first time, based on Two Sets of Independent Sites Model, m
- Li,Wang,Li,Wang
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p. 899 - 905
(2008/10/09)
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- Synthesis, characterization and thermal behaviour of solid-state compounds of yttrium and lanthanide benzoates
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Solid-state Ln(Bz)3?H2O compounds where Ln stands for trivalent yttrium or lanthanides and Bz is benzoate have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), X-ray powder diffractometry, infra
- Locatelli,Rodrigues,Siqueira,Ionashiro,Bannach,Ionashiro
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p. 737 - 746
(2008/10/09)
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- Thermal and spectroscopic investigations of new lanthanide complexes with 1,2,4-benzenetricarboxylic acid
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The new 1,2,4-benzenetricarboxylates of lanthanide(III) of the formula Ln(btc)?nH2O, where btc is 1,2,4-benzenetricarboxylate; Ln is La-Lu, and n=2 for Ce; n=3 for La, Yb, Lu; and n=4 for Pr-Tm were prepared and characterized by elemental analy
- Lyszczek
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p. 533 - 539
(2008/10/09)
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- Equilibria and structure of the lanthanide(III)-2-hydroxy-1,3- diaminopropane-N,N,N′,N′-tetraacetate complexes: Formation of alkoxo-bridged dimers in solid state and solution
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The complex formed between 1,3-diamino-2-hydroxypropane-N,N,N′, N′-tetraacetic acid (H4L-OH) and Nd3+ at pH 7.5 was found to be a dinuclear dimer in the solid state by X-ray crystallography. In the complex K4[Nd2(L-O)2-(H2O) 2]-14H2O each ligand is coordinated to both Nd 3+ atoms with an iminodiacetate group (the Nd3+-Nd 3+ distance is 3.9283(8) A). The alcoholic OH groups are deprotonated, and the alkoxo oxygens are coordinated to both Nd3+ in a bridging position. The Nd3+ ions are nine-coordinated with one water molecule per Nd(III) ion in the inner sphere. The complex K 4[Nd2(L-O)2(H2O)2] ·14H2O has an inversion center, and the space group is P1. Two of the K+ counterions are six-coordinated, while the other two K+ ions are eight-coordinated; polar polymeric water-K+ layers are formed between the apolar ligand layers via the bridging water molecules. The dinuclear dimer complexes are also present in aqueous solution. The proton relaxivities of the Gd3+ complex decrease with the increase of pH, and at pH > 6, the low relaxivity values indicate the probable absence of H2O in the inner sphere and the predominance of the eight-coordinated dimer species [Gd2(L-O)2]. 4- The results of ESI-TOF MS studies of the complexes of La 3+, Nd3+, and Lu3+ proved the formation of dinuclear dimers in dilute (0.25 mM) solutions. pH-potentiometric titrations indicate the formation of complexes with 1:1 (Ln(L-OH)-, Ln(HL-OH), and Ln2(L-O)24-) and 2:1 (Ln 2(L-O)+) metal-to-ligand ratios. The stability constants of the Ln(L-OH)- species increase from La3+ (log K = 10.19) to Lu3+ (log K = 14.08). The alcoholic OH group of the Ln(L-OH)- species dissociates at unusually low pH values. The pH range of dissociation shifts to lower and lower pH's with the increasing atomic number of the lanthanides. This pH range is about 4-7 for the La3+ complex and 1-4 for the Lu3+ complex. The results of 1D and 2D 1H and 13C NMR studies of the La3+ complex, the number and multiplicity of signals, and the values of coupling constants are in agreement with the dinuclear dimer structure of the complex in solution.
- Tircso, Gyula,Benyei, Attila,Bruecher, Erno,Kis, Anita,Kiraly, Robert
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p. 4951 - 4962
(2008/10/09)
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- Synthesis, characterization, thermal stability, reactivity, and antimicrobial properties of some novel lanthanide(III) complexes of 2-(N-salicylideneamino)-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene
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Two series of new lanthanide(III) complexes of the type [Ln(HSAT) 2(H2O)3Cl3] and [Ln(HSAT) 2(NO3)3], where Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Tm, Yb, or Lu, and HSAT = 2-(N-salicy
- Mohanan,Devi
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p. 600 - 609
(2008/10/09)
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- Extraction of lanthanide chlorides by binary extractants based on phosphinic acid derivatives
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The extraction of lanthanide chlorides by methyltrioctylammonium dialkylphosphinate, dialkyl-monothiophosphinate, or dialkyldithiophosphinate in toluene was studied. In all cases, extractable MA3 compounds were formed in an organic phase. The extractability of metals increased in the order La a considerable effect on the distribution of the lanthanide salts. The extraction capacity of the binary extradants toward lanthanum chloride decreased in the order methyltrioctylammonium dialkylphosphinate > methyltrioctylammonium dialkylmonothiophosphinate > methyltrioctylammonium dialkyldithiophosphinate. Copyright
- Egorova,Belova,Voshkin,Zhilov,Khol'kin
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p. 1781 - 1784
(2008/10/09)
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- Comparative study for stepwise chlorination-chemical vapor transport characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by the vapor complexes LnAlnCl3n+3
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A systematic study has been carried out for the stepwise chlorination-chemical vapor transport (SC-CVT) characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by the vapor complexes LnAlnCl3n+3 (where Ln = rare earth elements) under identical conditions. The results show that the total transported amount of the produced chlorides is the highest for YCl3; it is also high for ScCl3, but low for LaCl3, and then increases systematically from the early lanthanide chlorides to the end lanthanide chlorides except CeCl3, EuCl3 and GdCl3. The results also show that the main deposition temperature of the chlorides is in the increasing order ScCl3 3 3 and then with a systematically decreasing trend from the early lanthanide chlorides to the end lanthanide chlorides. Based on the literature data for the solid complexes LnAl3Cl12 and LnAl3Br12, a similar coordination structure assumption is introduced for the vapor complexes LnAl3Cl3n+3 from Ln = Sc to Ln = Lu with the same stoichiometry to explain the SC-CVT characteristics of the pure rare earth oxides from Sc2O3 to Lu2O3 using a 4f electron hybridization assumption.
- Wang, Zhi-Chang,Sun, Yan-Hui,Guo, Lei
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p. 109 - 113
(2008/10/08)
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- Synthesis, characterization and anticoagulant action of lanthanide complexes of warfarin
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Thirteen lanthanide complexes of warfarin, LnL3·nH2O [n = 6 (Ln = La-Yb) or n = 4 (Ln = Y); L = (C19H15O4)-] have been synthesized and characterized by elemental analyses, IR, 1H
- Jiao, Tian Quan,Wu, Ji Gui,Zeng, Fu Li,Fu, Yun Long,Deng, Ru Wen
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p. 725 - 735
(2008/10/09)
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- Solution enthalpies of hydrates LnCl3·xH2O (Ln=Ce-Lu)
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Trichlorides of the lanthanide elements Ln=Ce-Lu form: (a) isotypic hexahydrates LnCl3·6H2O with a coordination number (CN) 8 for the Ln3+ ions. (b) Two isotypic groups of trihydrates LnCl3·3H2O, in the first group Ln=Ce-Dy the CN is 8; the structure of the second group Ln=Er-Lu is unknown. With Ho no trihydrate exists; a dihydrate is formed. (c) Two isotypic groups of monohydrates LnCl3·H2O with unknown structure - Ln=Ce-Dy and Ln=Ho-Lu. For all compounds and for anhydrous chlorides LnCl3 solution enthalpies were measured with an isoperibolic calorimeter. The ΔsolH0 values do not depend only on the difference (lattice enthalpies/hydration enthalpies), but also on the state in solution. According to Spedding the CN of the Ln3+ ions against water changes from 9 to 8 between Nd and Sm, causing minima in the series of solution enthalpies. Dihydrates LnCl3·2H2O are found for Ln=Ce, Pr, Nd, Sm and presumably for Eu and Gd. They are not yet well characterised.
- Seifert,Funke
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- Investigation of the kinetics of the fluidized bed process for the dehydration of NdCl3·6H2O, TbCl3·6H2O and DyCl3·6H2O
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Dehydration of NdCl3·6H2O, TbCl3·6H2O and DyCl3·6H2O was carried out by fluidization in a gas mixture of Ar and HCl. In a series of isothermal experiments the effect of different process parameters was considered. Water vapour pressure of gas leaving the fluidized bed was estimated by using a simple mass balance. It was shown that the rate-limiting step of the overall dehydration process in the fluidized bed is removal of water vapour by a saturated bulk gas flow. However, the saturated gas phase data could not be thermodynamically interpreted. The reason to this is discussed.
- Sundstroem, Johan,Van Hong, Vu
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- Thermal decomposition kinetics and mechanism of lanthanide perchlorate complexes of 4-N-(4′-antipyrylmethylidene)aminoantipyrine
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The thermal decomposition behaviour of lanthanide perchlorate complexes of the Schiff base, 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA), have been studied using TG and DTG analyses. The phenomenological and kinetic aspects of the TG curves are inves
- Nair, M.K. Muraleedharan,Radhakrishnan
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p. 115 - 122
(2008/10/09)
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- Thermal decomposition of rare earth complexes with 2-amino-3,5-dichlorobenzoic acid
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The conditions of the thermal decomposition of the 2-amino-3,5-dichloro-benzoates of Y and lanthanides have been studied. During heating in air, the dihydrated complexes Ln(C6H2Cl2NH2COO) 3·2H2/
- Mrozek,Sikorska,Rzaczynska
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p. 707 - 720
(2008/10/09)
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- Thermodynamic Properties of the Rare Earth Element Vapor Complexes LnAl3Cl12 from Ln = La to Ln = Lu
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Systematic analysis of rare earth element complexes has been carefully carried out in the liquid and solid states but not in the gaseous state because of the lack of a complete set of experimental data for any kind of vapor complexes of all rare earth elements. Here we present experimental quenching results which suggest that the LnAl3Cl12 complexes are the predominant vapor complexes roughly in the temperature range 588-851 K and pressure range 0.01-0.22 MPa for all of the 14 rare earth elements Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. For these elements, thermodynamic functions of the reactions LnCl3(s) + 3/2Al2Cl6(g) = LnAl3Cl12(g) were calculated from the measurements. Those for the radioelement Pm were smoothly interpolated. The results show Gd divergences from the standard enthalpies and standard entropies from LaAl3Cl12 to LuAl3Cl12.
- Wang, Zhi-Chang,Wang, Lin-Shan
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p. 1536 - 1540
(2008/10/09)
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- The dehydration schemes of rare-earth chlorides
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The dehydration schemes of LaCl3·7H2O, CeCl3·7H2O, PrCl3·7H2O, PrCl3·7H2O, EuCl3·6H2O, GdCl3·OH2O, HoCl3·6H2O, ErCl3·OH2O, TmCl3·6H2O, YbCl3·OH2O and YCl3·6H2O have been investigated by the isothermal fluidizedbed technique. This technique is based on the fact that reactions proceed at a close approach to equilibrium and thus give rise to constant reaction rate regimes at constant gas flow and temperature in the bed. By injecting a small portion of HCl(g) (～1%) into the gas stream, hydrolysis is avoided, and dehydration to the monohydrate is recorded by both thermal analysis of the preheated inlet gas and chemical analysis of samples taken from the bed. Based on the present results, together with previous results on NdCl3·OH2O, TbCl3·6H2O and DyCl3·6H2O, dehydration schemes of all rare-earth chlorides except LuCl3 and ScCl3 are suggested.
- Hong, Vu Van,Sundstroem, Johan
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- Lanthanide Ion Chelates of Dibenzyl 1,1'-Diacetylferrocenebis(hydrazonatocarbodithioate)
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A new ligand, dibenzyl 1,1'-diacetylferrocenebis(hydrazonatocarbodithioate), Fe[C5H4C(CH3)=NNHCSSCH2C6H5)2] (H2Dafhb) and its chelates with lanthanide ions, Ln(Dafhb)Cl (Ln = lanthanide) have been prepared by the reaction of the H2Dafhb with LnCl3. All compounds were characterized by elemental analyses, IR, (1H) NMR, UV, electrolytic conductivity and TGA measurements. It is shown that the ligand coordinates to the metal in the thiol form and that one chloride ion participates in coordination. The chelates are non-electrolytes in DMF and are more thermostable than the ligand due to formation of chelate rings.
- Gang, Zhao,Yuan, Cao
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p. 1207 - 1217
(2008/10/09)
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- Enthalpy of formation of dysprosium dichloride
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We have measured the e.m.f.s of the solid-phase galvanic cells (-)Sr/SrCl2//BaCl2//DyCl2/Dy(+) and (-)Ca/CaCl2//BaCl2//DyCl2/Dy(+).The experimental results have been treated by the third law of thermodynamics by using published thermodynamic characteristi
- Goryushkin, V. F.,Podsevalov, V. P.,Zalymova, S. A.,Poshevneva, A. I.
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p. 130 - 132
(2007/10/02)
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- Low-temperature Specified Heat of Dysprosium and Lutetium Trichlorides
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The specific heat of DyCl3 and LuCl3 has been studied by adiabatic calorimetry in the range 6 - 240 K.The values of the thermodynamic functions under standard conditions have been determined.
- Tolmach, P. I.,Gorbunov, V. E.,Gavrichev, K. S.,Totrova, G. A.,Goryushkin, V. F.
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p. 1529 - 1532
(2007/10/02)
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