Herstellung,Analyse und röntgenographische Identifizierung der Dioxymonocarbonate des Lanthans und der Lanthanidenelemente

Zusammenfassung Von anderen Autoren angestellte thermische Zersetzungsanalysen der hydratisierten Oxalate, Carbonate und wasserfr. Carbonate der Lanthanide zeigten, daß viele Lanthanidenelemente VerbindungenLn ₂O_2+x (CO₃)_1–x bilden. Für die Verbindungen des La und des Pr ist der Wert vonx nahezu Null; bei den anderen Elementen nimmt er mit wachsender Ordnungszahl zu.In diesen Arbeiten wurden hydratisierte Oxalate und, im Falle des Lanthans, das hydratisierte Carbonat unter verschiedensten Bedingungen zersetzt. Die resultierenden Festkörper wurden durch chemische und röntgenographische Verfahren analysiert.Es wurden drei polymorphe kristalline Formen vonLn ₂O₂CO₃ gefunden und charakterisiert. Der monokline TypIA tritt beiLn=La, Pr und Nd auf, der tetragonale TypI beiLn=La, Nd, Sm, Eu und Gd; der hexagonale TypII beiLn=La, Pr, Nd, Sm und Gd.

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Preparation, analysis and X-ray identification of the dioxymonocarbonates of lanthanum and the lanthanide elements

Thermal decomposition studies of hydrated lanthanide oxalates and carbonates or anhydrous carbonates, carried out by others, have revealed the formation ofLn ₂O_2+x (CO₃)_1–x for many of the lanthanide elements. The value ofx is very close to zero for the La and Pr compounds and it increases with atomic number for the heavier elements.In these studies, hydrated oxalates and in the case of lanthanum, the hydrated carbonate have been decomposed under a variety of conditions and the resulting solid materials examined by chemical analysis and by X-ray diffraction methods.Three polymorphic crystalline forms ofLn ₂O₂CO₃ are observed and characterized. Monoclinic TypeIA has been observed forLn=La, Pr and Nd; tetragonal TypeI forLn=La, Nd, Sm, Eu, and Gd; and hexagonal TypeII forLn=La, Pr, Nd, Sm, and Gd.

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Mit 5 Abbildungen

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Diese Arbeit wurde von der United States Atomic Energy Commission unterstützt. Menschen aus drei Kontinenten haben sie erarbeitet und wünschen sie Professor Dr.H. Nowotny zu widmen.     

4,4′-Dipyridyl and 2,2′-dipyridyl complexes of rare-earth perchlorates

4,4-Dipyridyl and 2,2-dipyridyl complexes of rare-earth perchlorates of the formulaLn(4-dipy)₈(ClO₄)₃HClO₄ · 4H₂O (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, 4-dipy=4,4-dipyridyl) andLn(2-dipy)₃(ClO₄)₃ · 6H₂O (Ln=Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, 2-dipy = 2,2-dipyridyl) have been synthesized. The IR spectra of these compounds and other physical properties are discussed.

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4,4-Dipyridyl- und 2,2-Dipyridylkomplexe von Seltenerdmetallperchloraten

Zusammenfassung Es wurden 4,4-Dipyridylkomplexe des TypsLn(4-dipy)₈(ClO₄)₃HClO₄ · · 4 H₂O mitLn=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y und 2,2-Dipyridylkomplexe des TypsLn(2-dipy)₃(ClO₄)₃ · 6 H₂O mitLn=Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu und Y dargestellt. Die IR-Spektren und andere physikalische Eigenschaften werden diskutiert.

     

Thermal decomposition of 4,4′-dipyridyl complexes of light rare-earth thiocyanates in air atmosphere

The thermal decompositions of Ln(NCS)₃(4-dipy)₂·5H₂O were studied, whereLn=La, Pr, Nd, Sm, Eu and Y, and 4-dipy=4,4′-dipyridyl. The compounds are first dehydrated. During the thermal decomposition of Ln(NCS)₃(4-dipy)₂, deamination takes place. The transient products decompose with the formation of Ln₂O₂SO₄. The energies of activation for the first step of dehydration of the La, Pr, Nd, Sm and Eu complexes were determined.

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Zusammenfassung Es wurde die thermische Zersetzung von Ln(NCS)₃(4-dipy)₂.5H₂O mitLn=La, Pr, Nd, Sm, Eu, Y und 4-dipy=4,4′-Dipyridyl untersucht. Die Verbindungen werden zuerst dehydratiert. Bei der thermischen Zersetzung von Ln(NCS)₃(4-dipy)₂ findet eine Desaminierung statt. Die übergangsprodukte zersetzen sich unter Bildung von Ln₂O₂SO₄. Die Aktivierungsenergie für den ersten Schritt der Dehydratation der La-, Pr-, Nd-, Sm- und Eu-Komplexe wurde ermittelt.

     

Specific features of phase equilibriums in Ln–Ba–Fe–O systems

Formation of five-layered Ln_2–εBa_3+εFe₅O_15–δ phases [exhibiting nanoscale ordering with layer-by-layer location of the cations in the Ln–Ba–(Ln,Ba)–(Ln,Ba)–Ba–Ln perovskite-type structure] has occurred in the Ln–Ba–Fe–O (Ln = Y, Pr, Nd, Sm, Eu, and Gd) systems at 1100°С in air. Partial substitution of iron with cobalt (Ln_2–εBa_3+εFe_5–yCo_yO_15–δ, Ln = Nd, Sm, Eu) has stabilized formation of the ordered structure. The oxygen content in the complex oxides has been determined in air over a wide temperature range by means of high-temperature thermogravimetry and iodometric titration. The change in oxygen content with temperature for the phases with five-layered ordering was significantly smaller than for the disordered phases.     

Complex compounds of 2,2′-bipyridyl with some rare-earth bromides

The preparation of a series of new compoundsLnBr₃(2-bipy)₂·6H₂O (Ln=La, Pr, Nd, Eu, Gd) andLnBr₂OH(2-bipy)₂·4H₂O (Ln=Pr, Nd, Sm, Eu, Gd) is described. The IR spectra of these compounds are discussed. The thermal decomposition of compoundsLnBr₃(2-bipy)₂·6H₂O has been investigated.

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2,2-Bipyridylkomplexe einiger Seltenerdmetallbromide

Zusammenfassung Es wurden 2,2-Bipyridylkomplexe des TypsLnBr₃(2-bipy)₂·6H₂O (Ln=La, Pr, Nd, Sm, Eu, Gd) undLnBr₂OH(2-bipy)₂·4H₂O (Ln=Pr, Nd, Sm, Eu, Gd) dargestellt. Die IR-Spektren werden diskutiert. Die thermische Zersetzung von VerbindungenLnBr₃(2-bipy)₂·6H₂O wird untersucht.

     

Ln3UO6Cl3 (Ln=La,Pr, Nd) -. Die ersten Oxochlorouranate der Seltenen Erden

Ln₃UO₆Cl₃ (Ln=La, Pr, Nd) — The First Oxochlorouranates of the Rare Earths . The new compounds Ln₃UO₆Cl₃ (Ln=La, Pr, Nd) were prepared by heating stoichiometric amounts of LnOCl/Ln₂O₃/U₃O₈ (7 : 1 : 1) (Ln=La, Nd) and PrOCl/Pr₆O₁₁/U₃O₈ (12 : 1 : 2) in silica ampoules (5 d, 1000°C, Ln=La; 9 d 800°C, Ln=Pr, Nd) in the presence of an excess of chlorine [p(Cl₂, 25°C)=1 atm]. Single crystals were obtained by chemical transport reactions using chlorine [p(Cl₂, 25°C)=1 atm] as transport agent [T₂=1000°C→T₁=900°C (Ln=La); T₂=840°C→T₁=780°C (Ln=Pr, Nd)]. Crystals of Ln₃UO₆Cl₃ (Ln=La, Pr, Nd) were investigated by X-ray diffraction methods and La₃UO₆Cl₃ additionally by high resolution electron microscopy. The compounds Ln₃UO₆Cl₃ crystallize in the hexagonal spacegroup P6₃/m (No. 176) with Z=2 formula units per unit cell. Isotypical structure refinements resulted in R=3.04% respectively R_w=1.91% (Ln=La), R=4.72% respectively R_w=3.80% (Ln=Pr) and R=3.99% respectively R_w=2.49% (Ln=Nd). Uranium is coordinated with six oxygen atoms forming a trigonal prism. Lanthanide ions are 10-coordinated (6 oxygen atoms, 4 chlorine atoms).     

Regularities of change in the structural parameters of EuLnCuS<Subscript>3</Subscript> (Ln = La–Nd,Sm, Gd,Ho)

Regularities of change in the structural parameters of EuLnCuS₃ (Ln = La–Nd, Sm, Gd, Ho) at an annealing temperature of 970 and 1170 K have been established. A decrease in the Ln³⁺ ionic radius results in the consecutive change of structural types (STs) for the compounds: α-EuLnCuS₃ (Ln = La, Ce, Pr, Nd; BaLaCuS₃ ST) → β-EuLnCuS₃ (Ln = Ce, Pr, Nd; Ba2MnS₃ ST) → γ-EuLnCuS₃ (Ln = Sm, Gd, Ho; Eu₂CuS₃ST). The change of structural types for EuLnCuS₃ leads to a jump-like change in their unit cell parameters and the transformation of coordination polyhedra shaped as a one-capped trigonal prism LnS₇ (α and β phases) into an octahedron LnS₆ (γ phases). The appearance of morphotropic changes correlates with the tetrad effect.     

Thermal decomposition of light lanthanide diglycolates

The conditions of thermal decomposition of La, Ce(III), Pr, Nd, Sm, Eu and Gd diglycolates have been studied. On heating, the diglycolates of Ce(III), Pr, Eu and Gd lose crystallization water and yield anhydrous salts, which are then transformed into oxides. The diglycolates of La, Nd and Sm are decomposed in three stages. First, the diglycolates undergo dehydration to form the anhydrous salts, which are next decomposed to Ln₂O₂CO₃. In the last step the thermal decomposition of Ln₂O₂CO₃ to Ln₂O₃ takes place, accompanied by an endothermic effect.     

Schiff base derivatives of lanthanons,La(III), Pr(III), Nd(III) and Sm(III) complexes of bifunctional tetradentateSchiff base

Reactions of La(III), Pr(III), Nd(III) or Sm(III) nitrate with bifunctional tetradentateSchiff base, [o-HOC₆H₄C(CH₃): :NCH₂]₂, having the donor system HO–N–N–OH in 12 molar ratio have been investigated and found to yield new derivatives of the type [Ln(SBH₂)₂](NO₃)₃ [whereLn=La(III), Pr(III), Nd(III) or Sm(III) andSBH₂=Schiff base molecule, [o-HOC₆H₄C(CH₃) : NCH₂]₂. On the basis of elemental analyses, conductivity and magnetic measurements and infrared spectra, plausible structures for the resulting complexes have been indicated.     

Coordination compounds of bis[(1-cinnamoylhydrazonoethyl) cyclopentadienyl] iron lanthanide

Summary A new ligand, bis[(1-cinnamoylhydrazonoethyl)cyclopentadienyl] iron (BCHCI) has been prepared, and its complexes with lanthanides, Ln₂(BCHCI)₃Cl₆·nH₂O (Ln=Y, La, Ce, Pr, Nd, Sm, Eu, Dy, Ho. Er, Tm, Yb and Lu) have been made by reacting BCHCI with LnCl₃. A structure for these complexes, in which the ligand coordinates to lanthanide ions in its ketone form in a 1.51, molar ratio is suggested. The coordination numbers of the central metal ions are probably 8.     

X-ray and neutron powder diffraction study of the double perovskites Ba2LnSbO6 (Ln=La, Pr, Nd and Sm)

The crystal structures of Ba₂LnSbO₆ (Ln=La, Pr, Nd and Sm) at room temperature have been investigated by profile analysis of the Rietveld method using either combined X-ray and neutron powder diffraction data or X-ray powder diffraction data. It has been shown that the structure of Ba₂LnSbO₆ with Ln =La, Pr and Nd are neither monoclinic nor cubic as were previously reported. They are rhombohedral with the space group . The distortion from cubic symmetry is due to the rotation of the LnO₆/SbO₆ octahedra about the primitive cubic [111]_p-axis. On the other hand, the structure of Ba₂SmSbO₆ is found to be cubic. All compounds contain an ordered arrangement of LnO₆ and SbO₆ octahedra.     

4,4′-Dipyridyl complexes of rare-earth thiocyanates

4,4-Dipyridyl complexes of rare-earth thiocyanates of the formulaLn(4-dipy)₂(NCS)₃·5H₂O (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, 4-dipy = 4,4-dipyridyl) have been synthesized. The IR spectra of these compounds and other physical properties are discussed. The thermal decomposition of some compounds (in the order Gd ÷ Lu) has been investigated.

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4,4-Dipyridylkomplexe von Seltenerdmetallthiocyanaten

Zusammenfassung Es wurden 4,4-Dipyridylkomplexe des TypesLn(4-dipy)₂(NCS)₃·5H₂O mitLn = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu und Y dargestellt. Die IR-Spektren und andere physikalische Eigenschaften werden diskutiert und die thermische Zersetzung von einigen Verbindungen (in der Reihe Gd ÷ Lu) untersucht.

     

Thermal decomposition of lanthanide(III) complexes of bis-(salicylaldehyde)-1,3-propylenediimine Schiff base ligand

The thermal decomposition of lanthanide complexes, with a general formula: [LnL(NO₃)₂](NO₃), where Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, and Er; and L = bis-(salicyladehyde)-1,3-propylenediimine Schiff base ligand, was studied by thermogravimetric (TG) and derivative thermogravimetric (DTG) techniques. The TG and DTG data indicated that all complexes are thermostable up to 398 K. The thermal decomposition of all Ln(III) complexes was a two-stage process and the final residues were Ln₂O₃ (Ln = La, Nd, Sm, Gd, Dy, Er), Tb₄O₇, and Pr₆ O₁₁. The activation energies of thermal decomposition of the complexes were calculated from analysis of the TG-DTG curves using the Kissinger, Friedman, and Flynn-Well-Ozawa methods.     

Complexes of rare-earth metals with meconic acid

Two series of complexes of meconic acid (H₃ Mec) with rare-earths have been prepared by varying the preparative procedure. The compounds have the general formulae, [Ln(Mec) (H₂O)₂]·3 H₂O (whereLn=La, Ce, Pr, Nd, Sm, Ho and Y) and [Ln(HMec) (H₂ Mec) (H₂O)₂]·4 H₂O (whereLn=La, Pr, Nd and Sm). The infrared spectral data indicate that the carboxylate groups are bound to the rare-earth metal in a bidentate fashion. Thermal studies indicate that two water molecules are coordinated in each case. The complexes are probably polymeric.

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Komplexe von Seltenerd-Metallen mit Meconsäure

Zusammenfassung Es wurden zwei Reihen von Komplexen der Meconsäure (H₃ Mec) mit Seltenerd-Metallen mit den allgemeinen Formeln [Ln(Mec)(H₂O)₂]·3 H₂O (Ln=La, Ce, Pr, Nd, Sm, Ho, Y) und [Ln(HMec)₂(H₂ Mec) (H₂O)₂]·4 H₂O (Ln=La, Pr, Nd, Sm) hergestellt. Die IR-Spektren zeigen, daß die Carboxylat-Gruppen in zweizähniger Weise mit den Metallionen koordinieren; thermische Untersuchungen ergeben, daß in beiden Reihen jeweils zwei Wassermoleküle zusätzlich koordiniert sind. Die Komplexe weisen wahrscheinlich eine Polymerstruktur auf.

     

Kinetics of Ruddlesden-Popper Phase Formation: II. Mechanism of Nd2SrAl2O7 and Sm2SrAl2O7 Formation

Phase formation in the Ln₂O₃-SrO-Al₂O₃ system (Ln = Nd, Sm) was studied in the range 900-1530°C. Comparative examination of the kinetics of the synthesis of Ln₂SrAl₂O₇ oxides (Ln = La, Nd, Sm) showed that this reaction proceeds by a common mechanism and is substantially faster for neodymium and samarium complex aluminates than for lanthanum aluminate.     

Sur une série de solutions solides de formule Ca2−xLnxMnO4 (Ln = Pr,Nd, Sm,Eu, Gd)

A new series of solid solutions Ca_2−xLn_xMnO₄ (Ln = Pr, Nd, Sm, Eu et Gd) in which manganese is found in both oxidation state of +III and +IV, have a structure derived from that of K₂NiF₄. The cationic distribution in sites of nine-fold coordination is random.     

Hydrothermal phase equilibria in Ln2O3-H2O systems

Hydrothermal phase equilibria studies have been carried out in the Ln₂O₃-H₂O systems (Ln = La, Pr, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and the stability fields of the phases Ln(OH)₃ LnOOH and Ln₂O₃-C have been established in the pressure-temperature range of 25000 psi and 900° C. The sequioxides Ln₂O₃-C are stable only in the last four systems of Er to Lu along with the Ln(OH)₃ and LnOOH. The systems from Nd to Ho have only Ln(OH)₃ and LnOOH as stable phases and those from La to Pr have only Ln(OH)₃ as the stable phase. The unit cell parameters of trihydroxides deviate from the values reported in the literature and this is attributed to the contamination of CO₂ in the starting material.     

Verbindungen der Seltenerdelemente mit α-Benzoinoxim, 1. Mitt.

Zusammenfassung Substanzen der ZusammensetzungLnCl₃·3H₂ Box ^* (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Y) und LaBr₃·3 H₂ Box wurden isoliert und durch Thermoanalyse, IR-Absorptionsspektren und Röntgenstreuung charakterisiert.

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Compounds of the rare earth elements with -benzoin oxime

Compounds of compositionLnCl₃·3 H₂ Box ^* (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Y) and LaBr₃·3H₂ Box were isolated and characterized by thermoanalysis, IR spectroscopy and X-ray diffraction.

     

Synthese und Aufbau von (4-Picolinium)[LnCl4(H2O)3] (Ln = La,Ce, Pr,Nd)

Preparation and Crystal Structure of (4-Picolinium)[LnCl₄(H₂O)₃] (Ln = La, Ce, Pr, Nd) The complex water containing chlorides (4-Picolinium)[LnCl₄(H₂O)₃] (Ln = La, Ce, Pr, Nd) were prepared for the first time, and the crystal structures of (4-Picolinium)[LnCl₄(H₂O)₃] (Ln = La, Pr) were determined on single crystals by X-ray methods. The isotypic compounds crystallize with triclinic symmetry, space group P1 , Z = 2. Surprisingly there exist the dimeric complex anions [Ln₂Cl₈(H₂O)₆]^2? (Ln = La, Pr).     

Thermal decompositions of light lanthanide aconitates

The conditions of thermal decomposition of Y, La, Ce(III), Pr, Nd, Sm, and Gd aconitates have been studied. On heating, the aconitate of Ce(III) loses crystallization water to yield anhydrous salt, which then is transformed in to oxide CeO₂. The aconitates of Y, Pr, Nd, Sm, Eu and Gd decompose in three stages. First, aconitates undergo dehydration to form the anhydrous salts, which next decompose to Ln₂O₂CO₃. In the last one the thermal decomposition of Ln₂O₂CO₃ to Ln₂O₃ is accompanied by endothermic effect. Dehydration of aconitate of La undergoes in two stages. The anhydrous complex decomposes to La₂O₂CO₃; this subsequently decomposes to La₂O₃.