Ternäre Halogenide vom Typ A3MX6. I A3YCl6 (A = K,NH4, Rb,Cs): Synthese,Strukturen, Thermisches Verhalten. Über einige analoge Chloride der Lanthanide

Ternary Halides of the A₃MX₆ Type I. A₃YCI₆ (A = K, NH₄, Rb, Cs): Synthesis, Structures, Thermal Behaviour. Some Analogous Chlorides of the Lanthanides Reaction of the trichlorides MCl₃ (M = Y, Tb? Lu) with alkali chlorides AC1 (A = K, Rb, Cs) in evacuated silica ampoules at 850?900°C yields A₃MCl₆-type chlorides. (NH₄)₃YCl₆ is obtained via the ammonium-chloride route. The crystal structure of Rb₃YCl₆ (monoclinic, C2/c (no. 15), Z = 8, a = 2583(1)pm, b = 788.9(4)pm, c = 1283.9(7)pm, p = 99.63(4)°, R = 0.062, R_w = 0.050) is that of Cs₃BiCl₆. The Rb₃YCl₆/Cs₃BiCl₆ structure and the closely related structures of K₃MoCl₆ and In₂CI₃ are derived from the elpasolite-type of structure (K₂NaAlF₆) making use of the model of closest-packed layer structures. Cell parameters for the chlorides Rb₃MCl₆ (M = Y, Tb? Lu) and Cs₃YCl₆ and Cs₃ErCl₆ as well, which are all isostructural with Rb₃YCl₆, are given. The “system” (K, NH₄, Rb, Cs)YCl₆ has been investigated by DTA and high-temperature X-ray powder diffractometry.     

Mixed ligand chelates of some rare earth metals with diethylenetriamine-pentaacetic acid and dicarboxylic acids

By means of potentiometric studies evidence was found for the formation of 1:1:1 ternary chelates of the type:M(III)-DTPA-dicarboxylic acids [M(III)=La(III), Pr(III), Nd(III), Gd(III) or Dy(III); dicarboxylic acids = phthalic acid (PHA) or malonic acid (MLA)]. The formation constants (logK _MLL ) and free energies of formation (G°) have been evaluated. The order of stabilites with respect to the metal ions was La(III)MLA<PHA was observed.

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Gemischte Chelate einiger Selten-Erd-Metalle mit Diethylentriamin-pentaessigsäure und Dicarbonsäuren

Zusammenfassung Es wurden ternäre 1:1:1-Chelate folgenden Typs mittels potentiometrischer Untersuchungen nachgewiesen:M(III)-DTPA-Dicarbonsäure [M(III)=La(III), Pr(III), Nd(III), Gd(III) oder Dy(III); Dicarbonsäure = Phthalsäure (PHA) oder Malonsäure (MLA)]. Die Komplexbildungskonstanten (K _ML) und die Bildungsenthalphien (G°) wurden bestimmt. Bezüglich der Stabilität der Komplexe ergaben sich folgende Reihungen: La(III)MLA<PHA.

     

新的富金属三组元层状碲化物TaNi2Te2的合成和晶体结构

通过高温固相反应合成了标题化合物并测定了其晶体结构．结晶学参数：正交晶系，空间群Pnma，Z＝4，α＝0.6480(1)；b＝0.35639(6)，c＝1.6994(4) nm，V＝0.3925(1) nm，D_c＝9.37 g·cm~(-3)，λ(MoK_α)＝0.071069 nm，μ(MoK_α)＝514.43 cm~(－1)，F(000)＝932，最终偏离因子R＝0.051．TaNi_2Te_2是一新的富金属三级元层状碲化物，在结构中两层金属原子夹于碲原子层之间，形成对Ta原子的平面三角形碲配位和对Ni原子的三角锥碲配位．演化合物的一个重要结构特征是平面形的五元环TeNi_4孪合形成扩展结构而每个Ta原子夹于两个TeNi_4五元环之间．     

Silver(I) Double and Multiple Salts Containing the 1,3‐Butadiynediide Dianion: Coordination Diversity and Assembly with the Supramolecular Synthon Ag4⊂CC?CC⊃Ag4

A series of 13 silver(I) double and multiple salts containing 1,3‐butadiynediide, C₄^2?, were synthesized by dissolving the silver carbide Ag₂C₄ in a concentrated aqueous solution of one or more of the silver salts AgNO₃, AgCF₃CO₂, AgC₂F₅CO₂, AgF, AgBF₄, and AgPF₆. The 1,3‐butadiynediide anion invariably adopts a μ₄,μ₄ coordination mode in these compounds, which indicates that the Ag₄?C?C? C?C?Ag₄ moiety can be used as a new type of metalloligand supramolecular synthon for the construction of coordination networks. Fine‐tuning with various ancillary anionic ligands caused the Ag₄ aggregate at each ethynide terminus to adopt a butterfly‐shaped, planar, or barblike configuration, within which the silver–ethynide interactions can be classified into three types: σ, π, and mixed (σ,π). The effect of coexisting nitrile ligands and quaternary ammonium salts on supramolecular assembly with the above synthon was also explored. The hydrolysis of PF₆^? and BF₄^? led to the formation of the quadruple salt Ag₂C₄?4 AgNO₃?AgPF₂O₂?Ag₃PO₄ and a novel (F)₂(H₂O)₁₈ hydrogen‐bonded tape in the triple salt Ag₂C₄?2 AgF? 10 AgC₂F₅CO₂?CH₃CN?12 H₂O, respectively. The largest silver–ethynide cluster aggregate described to date, (C₄)₃@Ag₁₈, occurs in 3 Ag₂C₄? 12 AgC₂F₅CO₂?5[(BnMe₃N)C₂F₅CO₂]? 4 H₂O (Bn=benzyl).     

Ternary metal borides [La,Ce,Pr,Nd,Sm] Os4B4 and [Y,La,Ce,Pr,Nd,Sm,Gd,Tb] Ir4B4 with NdCo4B4-type structure

New ternary metal borides with compositionR. E. T ₄B₄ (R. E.=rare earth metal,T=transition metal) have been synthesized within the systems [La,Ce,Pr,Nd,Sm]–Os–B and [Y, La, Ce, Pr, Nd, Sm, Gd, Tb]–Ir–B. All compounds were found to be crystallizing with NdCo₄B₄-type structure. Magnetic measurements (80–300 K,Curie-Weiss behaviour, _p ~ 16K and µ_eff=9.94µ_B for TbIr₄B₄) indicate Y andR. E. elements (except Ce) to be trivalent in these compounds. The crystal chemistry of the isotypic series [Y,R. E.] [Os,Ir]₄B₄ is discussed.

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Ternäre Metallboride. [La,Ce,Pr,Nd,Sm] Os₄B₄ und [Y,La,Ce,Pr,Nd,Sm,Gd,Tb] Ir₄B₄ mit NdCo₄B₄-Struktur

Zusammenfassung Es wurden neue Metallboride der ZusammensetzungR. E. T ₄B₄ (R. E.=Seltenerdmetall,T=Übergangsmetall) innerhalb der Systeme [La,Ce, Pr,Nd,Sm]–Os–B und [Y,La,Ce,Pr,Nd,Sm,Gd,Tb]–Ir–B hergestellt. Alle Verbindungen kristallisieren entsprechend dem NdCo₄B₄-Typ. Magnetische Messungen (80–300K,Curie-Weiss-Verhalten, _p ~ 16K und µ_eff=9.94µ_B für TbIr₄B₄) zeigen an daß Y und dieR. E.-Elemente (ausgenommen Ce) in diesen Verbindungen trivalent sind. Die Kristallchemie der isotypen [Y,R. E.][Os,Ir]₄B₄-Verbindungen wird diskutiert.

     

Synthesis, structure and properties of Li2Rh3B2

Li₂Rh₃B₂ has been synthesized at 1000 °C from a stoichiometric mix of rhodium and boron and an excess of lithium. Li₂Rh₃B₂ crystallizes in the orthorhombic space group Pbam (no. 55, Z=2) with room temperature lattice constants a=5.7712(1) Å, b=9.4377(2) Å, c=2.8301(1) Å and cell volume 154.149(6) Å³. The structure was solved from single crystal X-ray diffraction yielding the final R indices (all data) R1=2.8% and wR2=4.7%. The structure is a distortion of the CeCo₃B₂ structure type, containing a network of Rh₆B trigonal prisms and short Li-Li contacts of 2.28(2) Å. Li₂Rh₃B₂ is a diamagnetic metal with a room temperature resistivity of 19 μΩ cm, as determined by magnetic susceptibility and single crystal transport measurements. The measured diamagnetism and electronic structure calculations show that Li₂Rh₃B₂ contains rhodium in a d¹⁰ configuration.     

Superconductivity—a source of surprises

Superconductivity is ascribed to a tendency of pairwise localization of conduction electrons. As a necessary condition in k space bands with very small as well as large dispersion need to be present at the Fermi level (“flat band/steep band”). The sufficient condition is a strong enough coupling of the flat band states to specific phonons in case of phonon-mediated superconductivity. The electron–phonon coupling parameter λ reveals a peak structure in the phonon q-space. These aspects are discussed for actual examples, e.g., rare earth carbides and carbide halides as well as MgB₂.     

Volumetric properties of the ternary system ethanol + chloroform + benzene at temperature range (288.15–313.15) K: Experimental data,correlation and prediction by cubic EOS

Densities ρ of the ternary system (ethanol + chloroform + benzene) and binaries (ethanol + chloroform) and (chloroform + benzene), have been measured at six temperatures (288.15, 293.15, 298.15, 303.15, 308.15, 313.15) K and pressure 101.33 kPa with an Anton Paar DMA 5000 digital vibrating tube densimeter. Excess molar volumes V^E were calculated from these densities data and fitted by the polynomial Redlich–Kister (for binary data) and Nagata and Tamura (for ternary data) equations. Radojkovi? et al. equation was used for the prediction of the V^E of ternary data. The obtained results have been explained in terms of different effects between molecules of present species, taking into consideration influence of temperature on them.     

Ternary Solution Mutual Diffusion Coefficients and Densities of Aqueous Mixtures of Sucrose with NaCl and Sucrose with KCl at 25°C

Ternary solution isothermal mutual diffusion coefficients (interdiffusion coefficients) have been measured for aqueous mixtures of 0.250 mol-dm^–3 sucrose (component 1) with 0.5 and 1.0 mol-dm^–3 NaCl or with 0.5 and 1.0 mol-dm^–3 KCl (salt = component 2) at 25.00°C using Rayleigh interferometry with computerized data acquisition. Densities were also measured. The volume-fixed diffusion coefficients (D _ij)_V show the following characteristics. At all compositions (D ₂₁)_V is much larger than (D ₁₂)_V and (D ₂₁)_V is a fairly significant fraction (33 to 68%) of (D ₁₁)_V. In addition, (D ₁₂)_V is slightly larger for mixtures containing NaCl than for those containing KCl at the same concentration, whereas (D ₂₁)_V is significantly larger for mixtures containing KCl. Values of (D ₁₁)_V are slightly larger for solutions containing KCl than for solutions containing NaCl. The observed trends imply that (D ₂₁)_V will probably exceed (D ₁₁)_V in both mixtures if concentrations of NaCl or of KCl are increased much further while maintaining the sucrose concentration at 0.250 mol-dm^–3. Finally, the solvent-fixed cross-term diffusion coefficients (D ₁₂)₀ and (D ₂₁)₀ are significantly larger than their corresponding (D ₁₂)_V and D ₂₁)_V.     

(Vapour + liquid) equilibrium in (N,N-dimethylacetamide + methanol + water) at the temperature 313.15 K

Total vapour pressures, measured at the temperature 313.15 K, are reported for the ternary mixture (N,N-dimethylacetamide + methanol + water), and for binary constituents (N,N-dimethylacetamide + methanol) and (N,N-dimethylacetamide + water). The present results are compared with previously obtained data for binary mixtures (amide + water) and (amide + methanol), where amide=N-methylformamide, N,N-dimethylformamide, N-methyl-acetamide, 2-pyrrolidinone and N-methylpyrrolidinone. Moreover, it was found that excess Gibbs free energy of mixing for binary mixtures varies roughly linearly with the molar volume of amide.