High pressure solubility data of carbon dioxide in (tri-iso-butyl(methyl)phosphonium tosylate + water) systems

Ionic liquids are attracting great attention nowadays due to their interesting properties which make them useful in a broad range of applications including reaction media or separation/capture of environmentally hazardous gases such as carbon dioxide. In many cases, for practical and/or economical reasons, the use of aqueous solutions of ILs would be preferable to their use as pure compounds.In this work, high pressure equilibrium data for the {carbon dioxide (CO₂) + tri-iso-butyl(methyl)phosphonium tosylate [iBu₃MeP][TOS] + water system were measured at temperatures ranging from (276 to 370) K and pressures up to 100 MPa. Measurements were performed using a high-pressure cell with a sapphire window that allows direct observation of the liquid–vapour transition. Mixtures with different IL concentrations were studied in order to check the influence of the amount of IL on the solubility of CO₂ in the aqueous mixture.The results show that the presence of IL enhances the solubility of CO₂ in the (IL + water) system revealing a salting-in effect of the IL on the solubility of CO₂. The appearance of a three phase region was observed for IL concentrations higher than 4 mol% of IL in water when working at pressures between 4 and 8 MPa and temperatures between (280 and 305) K. In this range, the upper limit of the VLE region observed is shown to increase with the temperature being almost independent of the IL initial concentration in the mixture.     

Chemical bonding analysis and properties of La7Os4C9—A new structure type containing C- and C2-units as Os-coordinating ligands

The new ternary carbide La₇Os₄C₉ was prepared by argon arc-melting of the elements followed by subsequent heat treatment at 900 °C for 250 h. The compound crystallizes monoclinic, in the space group C2/m (a=1198.5(2) pm, b=542.0(1) pm, c=1196.2(2) pm, β=111.04(1)°, V=725.2(2)×10⁶ pm³, Z=2). The structure was determined from single crystal X-ray diffraction data and refined to a residual of R₁=0.02 (wR₂=0.03) for 4812 unique reflections and 64 variable parameters. Electrical resistivity and magnetic susceptibility measurements characterize the compound as a Pauli-paramagnetic metal. The crystal structure contains bridging C- and terminal C₂-units as Os-coordinating ligands, thereby forming polyanions running along the [101] direction. The polyanions are composed of alternating Os(C₂)C₂ and OsC₃ units with the transition metal in distorted trigonal planar coordination. Charge compensation is ensured by La cations which are situated in-between the polyanions. The carbon-carbon bond (131 pm) within the C₂ pairs is slightly shorter than the value of a common C-C double bond, and is discussed on the basis of COHP curves on the one side, and with ELI-D and electron density distributions on the other side. The method of partial ELI-D decomposition is shown to be well suited for the characterization of separated DOS structures in terms of chemical bonding signatures provided by ELI-D. The Os-La interactions are shown to be of a polar multicenter-bonding type with Os playing the role of the electron donor. Compared to an acetylide the C₂ species were found to possess a significantly reduced bond order and an enhanced number of electrons in lone pair type spatial regions. This type of species cannot be simply classified in terms of model pictures such as C₂²⁻ and C₂⁴⁻, respectively.     

Ternary LiBH4–MgH2–NaAlH4 hydride confined into nanoporous carbon host for reversible hydrogen storage

Ternary hydride of LiBH₄–MgH₂–NaAlH₄ confined into carbo n aerogel scaffold (CAS) via melt infiltration for reversible hydrogen storage is proposed. Nanoconfinement of hydrides into CAS is obtained together with surface occupation of some phases, such as Al and/or LiH. Regarding nanoconfinement, not only multiple-step decomposition of LiBH₄–MgH₂–NaAlH₄ hydride reduces to about single step, but also reduction of dehydrogenation temperature is significantly observed, for example, ∆T up to 70 °C regarding last dehydrogenation step. Moreover, decomposition of NaBH₄ in nanoconfined sample can be done at 360 °C (dehydrogenation temperature in this study), which is 115 and 180 °C lower than that of NaBH₄ in milled LiBH₄–MgH₂–NaAlH₄ and bulk NaBH₄, respectively. The reaction of LiBH₄+NaAlH₄→LiAlH₄+NaBH₄ takes place during nanoconfinement and the decomposition of LiAlH₄ is observed, resulting deficient hydrogen content liberated. However, hydrogen content released (1st cycle) and reproduced (2nd–4th cycles) from this ternary hydride enhances up to 11% and 22% of full hydrogen storage capacity due to nanoconfinement. After rehydrogenation (T=360 °C and P(H₂)=50 bar H₂ for 12 h), NaBH₄, MgH₂, and Li₃AlH₆ are reversible, whereas Li₃AlH₆ and NaBH₄ in milled sample cannot be recovered due to deficient hydrogen pressure (T=360 °C and P(H₂)=80 bar) and probably evaporation of molten sodium during dehydrogenation, respectively. The latter results in inferior hydrogen content reproduced from milled sample to nanoconfined sample.     

4-ClCH2COAP-La(NO3)3-H2O和4-ClCH2COAP-LaCl3-H2O三元体系30℃时溶度测定

安替比林及其4位取代衍生物是较强的配位剂,可与不同的稀土盐作用生成组成各不相同的配合物,为了进一步探讨安替比林的衍生物对稀土离子的配位作用,我们研究了以4-一氯乙酰基安替比林(4-ClCH₂COAP)为配体与硝酸镧或氧化镧的三元水盐体系。     

Gleichgewichtsdruckmessungen im System Se/O/Br

Equilibrium Pressure Measurements in the System Se/O/Br The saturation pressure or saturation decomposition pressure of SeOBr_2,l, Se₂Br_2,l and SeBr_4,s were determined in a membran zero manometer. The decomposition behaviour follows from pressure measurements outside of saturation. From the equilibrium data are derived the Enthalpies of formation: Data see Inhaltsübersicht. Informations about the melting diagrams obtained via the barograms of the condensed compositions SeO₂/SeBr₄ and Se/Br.     

Synthesis and Crystal Structure of Rb6Pb5Cl16

The synthesis of a hitherto unknown 6 : 5 phase in the quasi-binary system RbCl/PbCl₂ and its structure determination is reported. The compound Rb₆Pb₅Cl₁₆ crystallizes in the tetragonal space group P4/mbm with a large variety of different coordination polyhedra for the cations. Special feature of the structure is a statistical distribution of Rb and Pb at one of the cation sites with a ratio of 1 : 3 as defined by electroneutrality. There is no evidence for symmetry reduction by ordering.     

Ca3Pd4Bi8: Kristall‐ und elektronische Struktur

Ca₃Pd₄Bi₈: Crystal and Electronic Structure Ca₃Pd₄Bi₈ (a = 10.814(4), b = 17.050(6), c = 4.149(4) Å) was prepared by heating the elements at 900 °C and investigated by single crystal X‐ray methods. The compound crystallizes in a new structure type (Pbam; Z = 2). Six Bi atoms form distorted trigonal prisms around the Pd atoms. The polyhedra share common corners, edges or faces building up a three dimensional Pd, Bi network, whose holes are occupied by Ca atoms. A special feature is a distorted octahedron of four Pd and two Bi atoms connected via short homonuclear bonds. The metallic behaviour of the compound derived from the bond lengths is discussed by LMTO band structure calculations.     

Synthese und Kristallstrukturen der Calcium‐Iridiumsilicide Ca3Ir4Si4 und Ca2Ir2Si

Synthesis and Crystal Structures of the Calcium Iridium Silicides Ca₃Ir₄Si₄ and Ca₂Ir₂Si The new compounds Ca₃Ir₄Si₄ und Ca₂Ir₂Si were prepared by reaction of the elemental components in sealed tantalum ampoules at 1200 °C. Their structures were determined from X‐ray single crystal data. Ca₃Ir₄Si₄(cubic, space group I4¯3m, a = 7.4171(2)Å, Z = 2) crystallizes with the Na₃Pt₄Ge₄ type structure. For Ca₂Ir₂Si (monoclinic, space group C2/c, a = 9.6567(5)Å, b = 5.8252(2)Å, c = 7.3019(4)Å, β = 100.212(2)°, Z = 4) a new structure was found. Chains of edge sharing, heavily distorted SiIr₄‐tetrahedra (Ir‐Si: 2.381 and 2.414Å) are connected via short Ir—Ir‐contacts (2.640Å) to form an open Ir/Si‐framework accommodating a three‐dimensional arrangement of calcium atoms (Ca—Ca: 3.413 ‐ 3.948Å).     

K3SbSe3, Rb3SbSe3 und Cs3SbSe3 – Synthese und Kristallstruktur

K₃SbSe₃, Rb₃SbSe₃, and Cs₃SbSe₃ – Synthesis and Crystal Structure The compounds K₃SbSe₃, Rb₃SbSe₃ and Cs₃SbSe₃ were synthesized by heating mixtures of Sb₂O₃ and an alkalicarbonate in a stream of hydrogen saturated by selenium in a temperature range between 750 °C and 800 °C. The compounds crystallize isostructural with Na₃AsS₃. A comparison of atomic distances and bond angles with those of the isostructural arsenic and bismuth compounds shows the effect of lone pairs.