Reaction of Lanthanum Carbonates with Nickel in Aqueous Medium

The system La₂(CO₃)₃-NiCO₃-H₂O and separate fragments of the systems Ni(OH)₃-NiCO₃-H₂O and LaNiO_{2 . 5}-CO₂-H₂O were studied by the isothermal crystallization technique. The compounds La₂(CO₃)₃·8H₂O, LaNi₅(CO₃)_{6 . 5}·xH₂O, and Ni(CO₃)_{0 . 6}(OH)_{0 . 8}·3H₂O and solid solutions based on lanthanum carbonate and lanthanum-nickel mixed carbonates were detected in the system. The intermetallic compound LaNi₅, which is highly competitive in characteristics with LaNi₅ cast alloy, was obtained by reduction of LaNi₅(CO₃)_{6 . 5}·xH₂O.     

非晶态镍硼酸盐结构的EXAFS研究

由摩尔比分别为1:2和1:8的NiCl₂·6H₂O和Na₂B₄O₇·10H₂O作为反应物, 合成两种非晶态镍硼酸盐, 同时通过水热法合成β-Ni(OH)₂. 化学分析和热重-微商热重法(TG-DTG)分析结果确定两种非晶态镍硼酸盐的分子组成分别为NiO·0.8B₂O₃·4.5H₂O和NiO·B₂O₃·3H₂O. 激光拉曼(Raman)实验结果表明镍硼酸盐样品中主要存在的硼氧阴离子为B₃O₃(OH)₅^2-和B₂O(OH)₆^2-. 同步辐射扩展X射线吸收精细结构(EXAFS)方法对样品进行结构解析, 通过数据拟合给出样品中Ni 原子周围近邻配位原子种类、配位数以及原子间距离. 用不同晶体结构作为标准对两种非晶态镍硼酸盐进行拟合的结果表明, 样品中Ni 原子周围局域结构与Ni₃B₂O₆晶体(ICSD No.31387)中的吻合较好. Ni 原子周围配位原子为O、B和Ni, 对于NiO·0.8B₂O₃·4.5H₂O, 配位数分别为5.7、3.8和3.8, 配位距离分别为0.208、0.263 和0.311 nm; 对于NiO·B₂O₃·3H₂O, 配位数分别为6.0、4.0 和4.0, 配位距离分别为0.207、0.262和0.310 nm.     

Syntheses and crystal structures of two new hydrated borates, Zn8[(BO3)3O2(OH)3] and Pb[B5O8(OH)]·1.5H2O

Two new hydrated borates, Zn₈[(BO₃)₃O₂(OH)₃] and Pb[B₅O₈(OH)]·1.5H₂O, have been prepared by hydrothermal reactions at 170 °C. Single-crystal X-ray structural analyses showed that Zn₈[(BO₃)₃O₂(OH)₃] crystallizes in a non-centrosymmetric space group R32 with a=8.006(2) Å, c=17.751(2) Å, Z=3 and Pb[B₅O₈(OH)]·1.5H₂O in a triclinic space group P1¯ with a=6.656(2) Å, b=6.714(2) Å, c=10.701(2) Å, α=99.07(2)°, β=93.67(2)°, γ=118.87(1)°, Z=2. Zn₈[(BO₃)₃O₂(OH)₃] represents a new structure type in which Zn-centered tetrahedra are connected via common vertices leading to helical ribbons _∞¹[Zn₈O₁₅(OH)₃]¹⁷⁻ that pack side by side and are further condensed through sharing oxygen atoms to form a three-dimensional _∞³[Zn₈O₁₁(OH)₃]⁹⁻ framework. The boron atoms are incorporated into the channels in the framework to complete the final structure. Pb[B₅O₈(OH)]·1.5H₂O is a layered compound containing double ring [B₅O₈(OH)]²⁻ building units that share exocyclic oxygen atoms to form a two-dimensional layer. Symmetry-center-related layers are stacked along the c-axis and held together by interlayer Pb²⁺ ions and water molecules via electrostatic and hydrogen bonding interactions. The IR spectra further confirmed the existence of both triangular BO₃ and OH groups in Zn₈[(BO₃)₃O₂(OH)₃], and BO₃, BO₄, OH groups as well as guest water molecules in Pb[B₅O₈(OH)]·1.5H₂O.     

Hydrothermal synthesis, characterization and thermochemistry of Ca2[B2O4(OH)2]·0.5H2O

A pure calcium borate Ca₂[B₂O₄(OH)₂]·0.5H₂O has been synthesized under hydrothermal condition and characterized by XRD, FT-IR and TG as well as by chemical analysis. The molar enthalpy of solution of Ca₂[B₂O₄(OH)₂]·0.5H₂O in HC1·54.582H₂O was determined. From a combination of this result with measured enthalpies of solution of H₃BO₃ in HC1·54.561H₂O and of CaO in (HCl + H₃BO₃) solution, together with the standard molar enthalpies of formation of CaO(s), H₃BO₃(s) and H₂O(l), the standard molar enthalpy of formation of −(3172.5 ± 2.5) kJ mol⁻¹ of Ca₂[B₂O₄(OH)₂]·0.5H₂O was obtained.     

Synthesis and thermochemistry of MgO·3B2O3·3.5H2O

A new magnesium borate MgO·3B₂O₃·3.5H₂O has been synthesized by the method of phase transformation of double salt and characterized by XRD, IR and Raman spectroscopy as well as by TG. The structural formula of this compound was Mg[B₆O₉(OH)₂]·2.5H₂O. The enthalpy of solution of MgO·3B₂O₃·3.5H₂O in approximately 1 mol dm⁻³ HCl was determined. With the incorporation of the standard molar enthalpies of formation of MgO(s), H₃BO₃(s), and H₂O(l), the standard molar enthalpy of formation of −(5595.02±4.85) kJ mol⁻¹ of MgO·3B₂O₃3.5H₂O was obtained. Thermodynamic properties of this compound was also calculated by group contribution method.     

Synthesis of Intermetallic Compounds LaNi5 and NdNi5 from Mixed Basic Carbonates of Lanthanum or Neodymium and Nickel

The possibility of obtaining powdered LaNi₅ and NdNi₅ intermetallic compounds by reaction of mixed basic carbonates La₂Ni_{1 0}(CO₃)₈(OH)_{1 0} · 54H₂O and Nd₂Ni_{1 0}(CO₃)₈(OH)_{1 0} · 14H₂O with calcium hydride in a hydrogen flow at 1073 K and 10⁵ Pa was studied.     

Synthesis and thermal decomposition of potassium trioxalatoaluminate hydrate

The preparation of pure K₃Al(C₂O₄)₃·mH₂O (2<m<3) is described. Dependent on the mode of preparation, the following were found to be contaminants of the desired product: K₂C₂O₄·1H₂O; KHC₂O₄; KHC₂O₄·H₂C₂O₄·2H₂O; H₂C₂O₄·2H₂O; different forms of aluminium oxide hydrate; K₄Al₂(OH)₂(C₂O₄)₄· (2+x)H₂O (0.7<x<1.7) and K₂Al₂(H₂O)₂(C₂O₄)₄· 4H₂O.     

Synthesis and characterization of homo- and heterobimetallic niobium and tantalum peroxo-polyaminocarboxylato complexes and their use as single or multiple molecular precursors for Nb-Ta mixed oxides

New water-soluble bimetallic peroxo complexes of niobium^V and/or tantalum^V with high-denticity polyaminocarboxylate ligands have been prepared, characterized from the spectroscopic point of view, and used as molecular precursors for Nb-Ta mixed oxides. Four new homobimetallic complexes, (gu)₃[Nb₂(O₂)₄(dtpaO₃)]·3H₂O 1, (gu)₃[Ta₂(O₂)₄(dtpaO₃)]·5H₂O 2, (gu)₃[Nb₂(O₂)₄(HtthaO₄)]·2H₂O 4 and (gu)₃[Ta₂(O₂)₄(HtthaO₄)]·3H₂O 5 and the corresponding heterometallic complexes, (gu)₃[NbTa(O₂)₄(dtpaO₃)]·2.5H₂O 3 and (gu)₃[NbTa(O₂)₄(HtthaO₄₎]·2H₂O 6 have been obtained. In these compounds, the in situ oxidation of the nitrogen atoms of the PAC ligands into N-oxide groups has been evidenced by IR spectroscopy and mass spectrometry. The thermal treatment of the homonuclear complexes in air at 700 or 800 °C, depending on the Ta content, provided Nb₂O₅ or Ta₂O₅ while the heteronuclear compounds led to the solid solution TaNbO₅. BET and SEM measurements have been carried out and comparison of the morphology of the samples prepared from homo- and heterometallic precursors is discussed.     

Synthesis, characterization, and thermochemistry of a new form of 2MgO·3B2O3·17H2O

A new magnesium borate, β-2MgO·3B₂O₃·17H₂O, has been synthesized by the method of phase transformation of double salt and characterized by XRD, IR, and Raman spectroscopy as well as by TG. The structural formula of this compound was Mg[B₃O₃(OH)₅]·6H₂O. The enthalpy of solution of β-2MgO·3B₂O₃·17H₂O in approximately 1 mol dm⁻³ HCl was determined. With the incorporation of the standard molar enthalpies of formation of MgO(s), H₃BO₃(s), and H₂O(l), the standard molar enthalpy of formation of −(10256.39±4.93) kJ mol⁻¹ of β-2MgO·3B₂O₃·17H₂O was obtained. Thermodynamic properties of this compound was also calculated by group contribution method.     

Supramolecular architectures constructed by lanthanum, amino acids and 1,10-phenanthroline via non-covalent bond interactions

Three supramolecular lanthanum coordination compounds of amino acids, with 1,10-phenanthroline (phen), [La₂(APA)₆(phen)₂(H₂O)₂](ClO₄)₆(phen)₄·2H₂O (1), [La₂(ABA)₆(phen)₂(H₂O)₂](ClO₄)₆ (phen)₆·4H₂O (2), and [La₂(AHA)₄(phen)₄](ClO₄)₆(phen)₄·2H₂O (3) (APA=3-aminopropionic acid; ABA=4-aminobutanoic acid; AHA=6-aminohexanoic acid) were synthesized and characterized by single crystal X-ray diffraction. The results show that the three coordination compounds are all composed of binuclear coordination cations built by metal-ligand coordination. Through hydrogen bonding and π-π stacking interactions, complex 1 forms a two-dimensional supramolecular sheet structure extending in the (001) plane, complex 2 forms a three-dimensional supramolecular network with many cavities occupied by ClO₄⁻ and lattice H₂O molecules, and complex 3 forms a two-dimensional supramolecular lamellar structure in the (100) plane.     

Chemie der Seltenerdmetalle, 20. Mitt.: Yttriumtartrate im neutralen und alkalischen Bereich

Zusammenfassung Es wurden die Verbindungen HYT ^*·4 H₂O, Y₄ T ₃·14 H₂O, LiYT·4 H₂O, NaYT·5 H₂O, KYT·3 H₂O, RbYT·4 H₂O, CsYT·4 H₂O, NH₄YT·3 H₂O, K₂YTOH·4 H₂O, K₃YT(OH)₂·4 H₂O, K₄YT(OH)₃·3 H₂O, K₅YT(OH)₄·3 H₂O, KYH₄ T ₂·3 H₂O, K₂YH₃ T ₂·5 H₂O, K₃YH₂ T ₂·4 H₂O, KY₂ T(OH)₃·5 H₂O, K₂Y₂ T(OH)₄·5 H₂O isoliert. Die Präparate wurden mit Hilfe von Thermoanalyse, IR-Absorptionsspektren und Röntgenstreuung näher charakterisiert und ihre Löslichkeit in Wasser untersucht.

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Some complexes of Yttrium with tartrates were isolated and the compounds characterised by thermogravimetric analysis, IR-spectroscopy and X-ray diffraction. Solubility in water was examined.

     

Thermochemistry of NaRb[B4O5(OH)4]·4H2O

The enthalpies of solution of NaRb[B₄O₅(OH)₄]·4H₂O in approximately 1 mol dm⁻³ aqueous hydrochloric acid and of RbCl in aqueous (hydrochloric acid + boric acid + sodium chloride) were determined. From these results and the enthalpy of solution of H₃BO₃ in approximately 1 mol dm⁻³ HCl(aq) and of sodium chloride in aqueous (hydrochloric acid + boric acid), the standard molar enthalpy of formation of −(5128.02 ± 1.94) kJ mol⁻¹ for NaRb[B₄O₅(OH)₄]·4H₂O was obtained from the standard molar enthalpies of formation of NaCl(s), RbCl(s), H₃BO₃(s) and H₂O(l). The standard molar entropy of formation of NaRb[B₄O₅(OH)₄]·4H₂O was calculated from the Gibbs free energy of formation of NaRb[B₄O₅(OH)₄]·4H₂O computed from a group contribution method.     

Evidence of 13 hybrid fluoroaluminates in the composition space diagram of the Al(OH)3–tren–HF–ethanol system

Thirteen phases are now evidenced in the composition space diagram of the Al(OH)₃–tren–HF–ethanol system at 190 °C. Solvothermal syntheses are performed under microwave heating. Six new organic–inorganic fluorides crystallise and their structures are determined: (H₃O)·[H₄tren]₂·(AlF₆)₃·6H₂O (P-1, Z = 2), [H₃tren]₂·(AlF₅(H₂O))₃·8H₂O (C2/c, Z = 8), [H₃tren]₄·(AlF₆)₂·(Al₂F₁₁)·(F)·10H₂O (P2₁/n, Z = 2), [H₃tren]₂·(Al₄F₁₈)·3.5H₂O (P6₃, Z = 2), [H₃tren]₂·(Al₄F₁₈) (P-1, Z = 1), and [H₃tren]₄·(Al₈F₃₅)·(OH)·H₂O (P-1, Z = 1). The existence domains are approximately located for all phases. Tren amine is tetraprotonated at high HF concentration, otherwise it is triprotonated. A protonated water cluster, H₃O⁺(H₂O)₆, appears in (H₃O)·[H₄tren]₂·(AlF₆)₃·6H₂O while a new Al₄F₁₈ unit, found in [H₃tren]₂·(Al₄F₁₈), is evidenced; it results from corner and edge sharing association of four AlF₆ octahedra. Finally, the structure of [H₃tren]₄·(Al₈F₃₅)·(OH)·H₂O revealed the largest known fluoroaluminate polyanion, built from eight vertex sharing AlF₆ octahedra, (Al₈F₃₅)¹¹⁻.     

Coordinate Structures of PrIII, GdIII, TmIII, and YbIII Complexes with Nitrilotriacetic Acids

The crystal and molecular structures of the [Pr^III(nta)(H₂O)₂]·H₂O (nta = nitrilotriacetic acids), K₃[Gd^III(nta)₂(H₂O)]·6H₂O, and K₃[Yb^III(nta)₂]·5H₂O complexes have been determined by single-crystal X-ray structure analyses. In [Pr^III(nta)(H₂O)₂]·H₂O, the Pr^IIINO₈ part forms a nine-coordinate pseudo-monocapped square antiprismatic structure in which one N and three O atoms are from one nta ligand in the same molecule, three O atoms from another nta ligand in the neighboring molecule and two O atoms from two coordinate water molecules. In K₃[Gd^III(nta)₂(H₂O)]·6H₂O, the [Gd^III(nta)₂(H₂O)^3- complex anion has a nine-coordinate pseudo-monocapped square antiprismatic structure in which each nta acts as a tetradentate ligand with one N atom of the amino group and three O atoms of the carboxylic groups. In K₃[Yb^III(nta)₂]·5H₂O, each nta also acts as a tetradentate ligand with one N atom of amino group and three O atoms of the carboxylic groups, but the [Yb^III(nta)₂ ^3- complex anion has an eight-coordinate structure with a distorted square antiprismatic prism. All the results including those for [Tm^III(nta)(H₂O)₂]·2H₂O confirm the inferences on the coordinate structures and coordination numbers of rare earth metal complexes with the nta ligand.     

Studies on synthesis, characterization and thermochemistry of Mg2[B2O4(OH)2]·H2O

A new magnesium borate Mg₂[B₂O₄(OH)₂]·H₂O has been synthesized by the method of phase transformation of double salt at hydrothermal condition and characterized by XRD, IR, TG and DSC. The enthalpy of solution of Mg₂[B₂O₄(OH)₂]·H₂O in 0.9764 mol L^–1 HCl was determined. With the incorporation of the enthalpies of solution of H₃BO₃ in HCl (aq), of MgO in (HCl+H₃BO₃) (aq), and the standard molar enthalpies of formation of MgO(s), H₃BO₃(s), and H₂O(l), the standard molar enthalpy of formation of –(3185.78±1.91) kJ mol^–1 of Mg₂[B₂O₄(OH)₂]·H₂O was obtained.This revised version was published online in November 2005 with corrections to the Cover Date.     

Verbindungen der Seltenerdelemente mit α-4-Dimethylaminobenzoinoxim

Zusammenfassung Es wurden VerbindungenLnCl₃·H₂ DBox ^* (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb) und La₂(DBox)₃·6 CH₃OH, Pr₂(DBox)₃·6 CH₃OH, Nd₂(DBox)₃·3 C₂H₅OH, Sm₂(DBox)₃· ·3 C₂H₅OH, Gd₂(DBox)₃·3 C₂H₅OH, Tb₂(DBox)₃·2 C₂H₅OH, DyH(DBox)₂·2 C₂H₅OH, HoH(DBox)₂·2 C₂H₅OH, ErH(DBox)₂, YH(DBox)₂·H₂O isoliert. Diese wurden mittels Thermoanalyse und Röntgenstreuung untersucht sowie ihre IR-Absorptionspektren gemessen und diskutiert.

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Compounds of rare earth elements with -4-dimethylaminobenzoinoxime

The compoundsLnCl₃·H₂ DBox ^* (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb) and La₂(DBox)₃·6 CH₃OH, Pr₂(DBox)₃·6 CH₃OH, Nd₂(DBox)₃·3 C₂H₅OH, Sm₂(DBox)₃·3 C₂H₅OH, Gd₂(DBox)₃· ·3 C₂H₅OH, Tb₂(DBox)₃·2 C₂H₅OH, DyH(DBox)₂·2 C₂H₅OH, HoH(DBox)₂·2 C₂H₅OH, ErH(DBox)₂ and YH(DBox)₂·H₂O were isolated, and studied by thermoanalysis and X-ray diffraction. Their IR absorption spectra were recorded and are discussed.

     

Thermal decomposition of rare earthp-aminosalicylates in air atmosphere

The conditions of thermal decomposition of thep-aminosalicylates of Y, La and the lanthanides from Ce(III) to Lu have been studied. On heating, the hydrated complexes of La and the light lanthanides decompose to the oxides with the intermediate formation of Ln₂[H₂N·C₆H₃(O)COO]₃. Only the complex of La decomposes to La₂O₃ through La₂[H₂N·C₆H₃(O)COO]₃ and La₂O₂CO₃. The anhydrous complexes of the heavy lanthanides decompose directly to the oxides, whereas the anhydrous complex of Y decomposes to Y₂O₃ via Y₂[H₂N·C₆H₃(O)COO]₃ formation. During heating, the hydrated complexes lose crystallization water and decompose simultaneously, and the endothermic effect of dehydration is masked by the strong exothermic effect of burning of the organic ligand.

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Zusammenfassung Es wurden die Bedingungen für die thermische Zersetzung derp-Aminosalicylate von Y, La und der Lanthanoide von Ce(III) bis Lu untersucht. Beim Erhitzen zersetzen sich die hydratierten Komplexe von La und der leichteren Lanthanoide unter Bildung des Zwischenproduktes Ln₂[H₂NC₆H₃(O)COO]₃ in ihre Oxide. Nur der Komplex mit La zersetzt sich zu La₂O₃ über die Zwischenstufen La₂[H₂NC₆H₃(O)COO]₃ und La₂O₂CO₃. Die wasserfreien Komplexe der schweren Lanthanoide zersetzen sich direkt in die Oxide, wÄhrend sich der wasserfreie Komplex von Y über die Bildung von y₂[H₂NC₆H₃(O)COO]₃ in y₂O₃ zersetzt. Beim Erhitzen verlieren die hydratierten Komplexe ihr Kristallwasser und zersetzen sich gleichzeitig, der endotherme Effekt der Dehydratation wird durch den starken exothermen Effekt der Verbrennung der organischen Liganden überdeckt.

     

Hexamolybdoaluminates and Hexamolybdochromates of Some Trivalent Lanthanides and Americium

The reactions of some rare-earth elements (La, Ce, Sm, Lu, Gd) and Am(III) with heteropolymolybdate anions are studied. The complexation rate constants of Am(III) in a solution with Al(OH)₆Mo₆O₁₈ ^3- and Cr(OH)₆MoO₁₈ ^3- ₆ (₁ = 18 ± 6 and 25 ± 5, respectively) are determined by spectral methods. The Ln[Al(OH)₆Mo₆O₁₈] · nH₂O, Eu[Cr(OH)₆Mo₆O₁₈] · nH₂O, and Am[Al(OH)₆Mo₆O₁₈] · nH₂O isostructural compounds are synthesized. The crystal structure of the Sm[Al(OH)₆Mo₆O₁₈] · 11H₂O complex was determined by the X-ray diffraction analysis. The results of spectroscopic and thermogravimetric studies of the obtained compounds are presented.     

Structural characterizations and magnetic properties of three new reduced molybdenum phosphates

Three new molybdophosphates, [Co(dien)₂]·(H₃dien)₆·{[CoMo₁₂O₂₄(OH)₆(HPO₄)₂(PO₄)₆][Co(Hdien)]₂[CoMo₁₂O₂₄(OH)₆(PO₄)₈]}·(dien)·4H₃O·5H₂O (1), (H₃dien)₄[MMo₁₂O₂₄(OH)₆(HPO₄)₄(PO₄)₄]·10H₂O [M=Co for (2), Ni for (3); dien=diethylenetriamine], have been synthesized by employing hydrothermal method and characterized by single crystal X-ray diffraction. Compound 1 is built up of Co[P₄Mo₆]₂ units as the structural motif covalently linked by [Co(Hdien)] complex subunits to yield an unusual 1-D chain. Compounds 2 and 3 are isomorphic and both display covalent discrete M[P₄Mo₆]₂ cluster structures which are linked by the hydrogen bonds to form 3-D supramolecular networks. Both 1 and 2 display antiferromagnetic interaction and these three compounds all exhibit intensive photoluminescence.     

UR-spektroskopische Untersuchungen an zeolithischen Heptagermanaten

Zusammenfassung Der direkte Nachweis von H₃O⁺-Ionen bzw. OH^–-Ionen in zeolithischen Germanaten wird durch UR-spektroskopische Untersuchungen erbracht. Hydronium-Ionen liegen vor beiM(I)₃HGe₇O₁₆·nH₂O sowie bei Ba- und Pb-Zeolithen der FormM(II)_2–x H_2x Ge₇O₁₆·nH₂O, während man in Ba- und Pb-Zeolithen der ZusammensetzungM(II)_2+x Ge₇O₁₆(OH)_2x ·nH₂O Hydroxyl-Ionen beobachtet.

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By IR-spectroscopic investigations of zeolitic germanates of formulaM(I)₃HGe₇O₁₆·nH₂O as well as of Ba- and Pb-zeolites of formulaM(II)_2–x H_2x Ge₇O₁₆·nH₂O the presence of H₃O⁺-ions can be detected. On the other hand inM(II)_2+x Ge₇O₁₆(OH)_2x ·nH₂O (M=Ba, Pb) hydroxyl ions are observed.

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