- Synthesis of REF3 (RE = Nd, Tb) nanoparticles via a solvent extraction route
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NdF3 and TbF3 nanoparticles were successfully synthesized via a solvent extraction route using Cynex923 (R3P{double bond, long}O). X-ray diffraction (XRD) study showed that pure hexagonal phase NdF3 and pure ort
- Guo, Fuqiang,Li, Hongfei,Zhang, Zhifeng,Meng, Shulan,Li, Deqian
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- Kinetic study of the thermal decomposition of the compound of terbium(III) trifluoromethanesulfonate and hexamethylphosphoramide (HMPA) employing both Zsako?'s and nonlinear methods
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Terbium trifluoromethanesulfonate compound with hexamethylphosphoramide was synthesized and characterized. Thermogravimetric data with three heating rates were used to obtain kinetic parameters such as activation energy (Ea), reaction order (n) and preexponential factor (k0). The results obtained by two different methods, Zsa?'s and a nonlinear one, are compared.
- Pedrosa,Araújo Melo,Scatena Jr.,Borges,Zinner,Silva
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- The new carbodiimide Li2Gd2Sr(CN2) 5 having a crystal structure related to that of Gd 2(CN2)3
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The new carbodiimide compounds Li2RE2Sr(CN 2)5 (RE = Sm, Gd, Eu, Tb) were prepared by a straight forward solid state metathesis reaction of REF3, SrF2, and Li2(CN2) at around 600 °C. The crystal structure of Li2Gd2Sr(CN2)5 was solved based on X-ray single-crystal diffraction data. Corresponding Li2RE 2Sr(CN2)5 compounds were analyzed by isotypic indexing of their powder patterns. The crystal structure of Li 2Gd2Sr(CN2)5 can be well related to that of Gd2(CN2)3, because both structures are based on layered structures composed of close packed layers of [N=C=N] 2- sticks, alternating with layers of metal ions. The crystal structure of Li2Gd2Sr(CN2)5 can be considered to contain an ABC layer sequence of [N = C=N]2- layers with the interlayer voids being occupied by (three) distinct types of cations. Copyright
- Unverfehrt, Leonid,Stroebele, Markus,Meyer, H.-Juergen
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- THERMAL DECOMPOSITION OF CURIUM TETRAFLUORIDE AND TERBIUM TETRAFLUORIDE.
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The thermal decompositions of both curium and terbium tetrafluorides have been studied using mass spectrometry to monitor the effusate from a Knudsen cell containing the condensed fluoride. Curium tetrafluoride was found to decompose at 330-430 degree C in vacuum. A Second Law enthalpy of 26. 3 plus or minus 2 kcal/mole (at 370 degree C) is derived from van't Hoff plots of results obtained for the decomposition reaction. Decomposition fluorine pressures are derived and comparison is made with related studies of terbium tetrafluoride carried out in conjunction with the curium experiments. The results are compared both with data reported in the literature for lanthanide and actinide tetrafluorides and with predictions that have been made for CmF//4.
- Gibson,Haire
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- Rapid synthesis of single-crystalline TbF3 with novel nanostructure via ultrasound irradiation
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Terbium fluoride (TbF3) nanopeanut has been successfully synthesized via a mild sonochemical route from an aqueous solution of terbium nitrate and fluoroborate without any template or organic additive. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence (PL) spectra were utilized to characterize the synthesized samples. The morphologies and optical properties of the obtained TbF3 nanopeanut can be tuned by ultrasound irradiation as well as the fluoride source. The prepared TbF3 nanopeanut shows extraordinarily high room temperature photoluminescence intensity comparing to the products prepared by stirring. The possible formation mechanism is proposed in this paper.
- Zhu, Ling,Liu, Yangjia,Fan, Xizhi,Yang, Daowu,Cao, Xueqiang
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- Lanthanide pentafluorophenolates. Synthesis, structure and luminescent properties
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The pentafluorophenolates of lanthanides Ln(OC6F 5)3 (Ln = Nd (1), Tb (2), Er (3)) were prepared by the reactions of pentafluorophenol with appropriate silylamides Ln[N(SiMe 3)2]3 in benzene or toluene solution. The same reactions in ether or methanol medium afforded the solvated complexes Ln(OC 6F5)3(Et2O)3 (Ln = Nd (4), Eu (5), Tb (6), Er (7), Gd (8)) or Nd(OC6F5) 3(MeOH)3 (9), respectively. The phenanthroline complexes Ln(C6F5O)3(phen) (Ln = Pr (10), Nd (11), Er (12)), Ln(OC6F5)3(phen)2 (Ln = Sm (13), Tb (14), Ho (15), Ln(OC6F5)3(phen) 2(Et2O) (Ln = Eu (16), Yb (17)), and Ln(OC 6F5)3(phen)(Et2O)3 (Ln = Eu (18), Nd (19), Ce (20), Dy (21)), Ln(OC6F5) 3(phen)2(H2O) (Ln = Sm (22), Ho (23)), and Gd(OC6F5)3(phen)2(MeOH) (24) were obtained when the reactions were carried out in the presence of 1,10-phenanthroline. The complexes with pyridine Tb(OC6F 5)3(py)5 (25) and 2,2′-bipyridyl Ln(OC6F5)3(bpy)2 (Ln = Tb (26), Yb (27)) were synthesized similarly. Compounds 7, 22, 23, and 24 were characterized by X-ray analysis. The complexes Ln(OC6F5)3 decompose above 150 C in vacuum to give lanthanide fluorides and octofluorodibenzo-p-dioxine. Phenanthroline derivatives are stable up to 310 C. Luminescence spectra of all the obtained complexes in visible region contain a broad band of ligand-centered emission peaked at 405-415 nm. Spectra of samarium 13, europium 5, 16, 18 and terbium 14, 25, 26 derivatives display also the characteristic narrow bands of Sm3+, Eu3+ and Tb 3+ ions.
- Maleev, Alexander A.,Fagin, Anatoly A.,Ilichev, Vasily A.,Lopatin, Mikhail A.,Konev, Alexey N.,Samsonov, Maksim A.,Fukin, Georgy K.,Bochkarev, Mikhail N.
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p. 126 - 132
(2013/11/19)
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- X-ray magnetic circular dichroism (XMCD) study of a methoxide-bridged DyIII-CrIII cluster obtained by fluoride abstraction from cis-[CrIIIF2(phen)2]+
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An isostructural series of dinuclear chromium(III)-lanthanide(III) clusters is formed by fluoride abstraction of cis-[CrF2(phen) 2]+ by Ln3+ resulting in LnF3 and methoxide-bridged Cr-Ln clusters (Ln = Nd (1), Tb (2), Dy (3)) of formula [CrIII(phen)2(μ-MeO)2Ln(NO3) 4]?xMeOH (x = 2-2.73). In contrast to fluoride, methoxide bridges in a nonlinear fashion, which facilitates chelation. For 3, X-ray magnetic circular dichroism (XMCD) provides element-specific magnetization curves that are compared to cluster magnetization and susceptibility data acquired by SQUID magnetometry. The combination of XMCD and SQUID is able to resolve very small magnetic coupling values and reveals a weak Cr III-DyIII coupling of j = -0.04(3) cm-1. The DyIII ion has a ground-state Kramers doublet of mJ = ±13/2, and the first excited doublet is found to be mJ = ±11/2 at an energy of δ = 57(21) cm-1. The Cr III ion exhibits a uniaxial anisotropy of DCr = -1.7(1.0) cm-1. Further, we observe that a weak anisotropic coupling of dipolar origin is sufficient to model the data, suggesting that methoxide bridges do not play a significant role in the magnetic coupling for the present systems.
- Dreiser, Jan,Pedersen, Kasper S.,Birk, Torben,Schau-Magnussen, Magnus,Piamonteze, Cinthia,Rusponi, Stefano,Weyhermueller, Thomas,Brune, Harald,Nolting, Frithjof,Bendix, Jesper
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p. 7842 - 7847
(2012/09/22)
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- Optically active uniform potassium and lithium rare earth fluoride nanocrystals derived from metal trifluroacetate precursors
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This paper reports the first systematical synthesis of near-monodisperse potassium and lithium rare earth (RE) fluoride (K(Li)REF4) nanocrystals with diverse shapes (cubic KLaF4 and KCeF4 wormlike nanowires, nanocubes and
- Du, Ya-Ping,Zhang, Ya-Wen,Sun, Ling-Dong,Yan, Chun-Hua
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p. 8574 - 8581
(2011/01/06)
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- Thermochemical studies on the lanthanoid complexes of trifluoroacetic acid
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The thermal decomposition of the lanthanoid complexes of trifluoroacetic acid (Ln(CF3COO)3·3H2O; Ln = La-Lu) was studied by TG and DTA methods. The Ln(CF3COO) 3·3H2O complexes decompose in several stages; first dehydrate to the anhydrous state, then followed by decomposition of the anhydrous salt to a stable product of LnF3. From the endothermic and exothermic data of Ln(CF3COO)3·3H2O complexes, pyrolysis behavior of the complexes is classified into three groups: (1) La-Pr salts; (2) Nd-Gd salts; (3) Tb-Lu salts. It has been shown that all the final decomposition products were found to result in the formation of LnF3.
- Yoshimura,Ohara
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p. 573 - 576
(2008/10/09)
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- Hydrothermal synthesis of rare-earth fluoride nanocrystals
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In this paper, a hydrothermal synthetic route has been developed to prepare a class of rare-earth fluoride nanocrystals, which have shown gradual changes in growth modes with decreasing ionic radii and may serve as a model system for studying the underlying principle in the controlled growth of rare-earth nanocrystals. Furthermore, we demonstrate the functionalization of these nanocrystals by means of doping, which have shown visible-to-the-naked-eye green up-conversion emissions and may find application in biological labeling fields.
- Wang, Xun,Zhuang, Jing,Peng, Qing,Li, Yadong
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p. 6661 - 6665
(2008/10/09)
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- Mass and FTIR spectroscopic investigations of gaseous manganese tetrafluoride
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Knudsen effusion mass spectrometry has been applied to establish the optimum in situ conditions for the MnF4 synthesis. MnF4 has been generated in the gas phase over the MnF3(s)-TbF4(s) system at 650-780 K in the Knudsen cell. Under the same conditions the supplying gas for the matrix isolation IR spectra was formed. The infrared spectrum of argon-isolated MnF4 molecules has been obtained for the first time. A Td symmetry is suggested for the MnF4 molecule.
- Nunziante Cesaro,Rau,Chilingarov,Balducci,Sidorov
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p. 179 - 181
(2008/10/08)
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- Identification of gaseous cobalt tetrafluoride: MS and FTIR spectroscopic studies
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The existence of gaseous CoF4-a species with an unusually high degree of oxidation of the metal-has been demonstrated by means of Knudsen effusion mass spectrometry and FTIR spectroscopy. The Knudsen effusion mass spectrometry method has been applied to investigate the gas-phase composition over the CoF3(s)-TbF4(s) system and to establish the optimum in situ conditions for CoF4 synthesis. The electron impact mass spectrum of the CoF4 molecule has been obtained. From the infrared spectrum of argon-isolated CoF4 molecules, the Co-F stretching mode has been detected at 767.8 cm-1.
- Rau, Juliet V.,Cesaro, Stella Nunziante,Chilingarov, Norbert S.,Balducci, Giovanni
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p. 5695 - 5697
(2008/10/08)
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- Judd-Ofelt intensity parameters of trivalent lanthanide ions in a NaPO3-BaF2 based fluorophosphate glass
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The spectroscopic properties of the trivalent lanthanide ions Pr3+, Nd3+, Sm3+, Eu3+, Tb3+, Dy3+, Ho3+, Er3+ and Tm3+ in the fluorophosphate glass 75NaPO3-24BaF2-1LnF3 (where Ln = lanthanide ion) are described. The dipole strengths of the transitions in the absorption spectrum are parameterized in terms of three Ωλ (λ = 2, 4 and 6) Judd-Ofelt intensity parameters.
- Van Deun,Binnemans,Gorller-Walrand,Adam
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- Synthesis and Study of Gadolinium(III), Terbium(III) and Dysprosium(III) Pentafluorobenzoates
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The compounds Ln(C6F5COO)3 · n H2O (Ln = Gd, Tb, Dy; n = 2, 2, and 1, respectively) were synthesized and characterized by IR spectroscopy, magnetic properties, and thermal analysis. Their thermolysis at T > 350°C gives LnF3.
- Myachina,Sheludyakova,Ikorskii,Lisoivan,Fadeeva,Larionov
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p. 837 - 838
(2007/10/03)
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- Thermodynamics of the rhombohedral-cubic phase transition of ROF with R=Y, La, Pr, Nd, Sm-Er
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The temperatures and enthalpies of the rhombohedral-cubic phase transition of stoichiometric ROF with R=Y, La, Pr, Nd, Sm-Er, have been determined by differential scanning calorimetry. The temperatures of transition are found in the range 742-880 K in sat
- Petzel,Marx,Hormann
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