Der chemische Transport von FeP2 und FeP4 mit lod

Chemical Transport of FeP₂ and FeP₄ with Iodine Experiments on the chemical transport of FeP₂ and FeP₄ with iodine are discussed, considering the gaseous molecules I₁, I₂, FeI₂, Fe₂I₄, FeI₃, Fe₂I₆, PI₃, P₂I₄, P₄, P₂, and P. Thermodynamic calculations give δH°(298) = 56.322 kcal and ΔS°(298) = 39.5 cal/K for the reaction FeP_2,f + I₂ = FeI₂ + 0.5 P₄ and δG°(923) = 35.8 kcal for the reaction FeP_4,f + I₂ = FeI₂ + P₄.     

The Oxidation of Heterogeneous Tl/Ni/P‐Alloys — Preparation and Crystal Structures of the Thallium Nickel Phosphates TlNi4(PO4)3, Tl4Ni7(PO4)6, and Tl2Ni4(P2O7)(PO4)2

Single crystals of the first anhydrous thallium nickel phosphates were prepared by reaction of heterogeneous Tl/Ni/P alloys with oxygen. TlNi₄(PO₄)₃ (pale‐yellow, orthorhombic, space group Cmc2₁, a = 6.441(2)Å, b = 16.410(4)Å, c = 9.624(2)Å, Z = 4) crystallizes with a structure closely related to that of NaNi₄(PO₄)₃. Tl₄Ni₇(PO₄)₆ (yellow‐brown, monoclinic, space group Cm, a = 10.711(1)Å, b = 14.275(2)Å, c = 6.688(2)Å, β = 103.50(2)°, Z = 8) is isotypic with Na₄Ni₇(PO₄)₆, and Tl₂Ni₄(P₂O₇)(PO₄)₂ (brown, monoclinic, space group C2/c, a = 10.389(2)Å, b = 13.888(16)Å, c = 18.198(3)Å, β = 103.1(2)°, Z = 8) adopts the K₂Ni₄(P₂O₇)(PO₄)₂ structure. Tl₂Ni₄(P₂O₇)(PO₄)₂ could also be prepared in nearly single phase form by reaction of Tl₂CO₃, NiO, and (NH₄)₂HPO₄.     

Darstellung von Schwermetallchalkogenid-Einkristallen durch chemischen Transport mit Aluminiumchlorid

Zusammenfassung Durch chemischen Transport mit wasseerfr. AlCl₃ als Transportmittel konnten folgende Schwermetallsulfide und-selenide in Form von Einkristallen erhalten werden: Cr₂S₃, Cr₃S₄, Cr₅S₆, Cr₇S₈, CrS, Cr₂Se₃, Cr₇Se₈, CoS₂, CoS, (Co), NiS₂, NiS, ZnCr₂S₄, CdCr₂S₄, MnCr₂S₄, ZnCr₂Se₄, CdCr₂Se₄, HgCr₂Se₄, CuCr₂Se₄, NiCr₂S₄, Ni_0,95Cr_0,05S, Ni_0,83Cr_0,17S, Ni_0,75Cr_0,25S. Der Mechanismus des Transports mit AlCl₃ und die Darstellung größerer Einkristalle werden diskutiert.

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Growing of chalcogenide single crystals by chemical transport with aluminium chloride

Single crystals of the following compounds have been grown by chemical transport with anhydrous aluminium chloride as transporting agent: Cr₂S₃, Cr₃S₄, Cr₅S₆, Cr₇S₈, CrS, Cr₂Se₃, Cr₇Se₈, CoS₂, CoS, (Co), NiS₂, NiS, ZnCr₂S₄, CdCr₂S₄, MnCr₂S₄, ZnCr₂Se₄, CdCr₂Se₄, HgCr₂Se₄, CuCr₂Se₄, NiCr₂S₄, Ni_0,95Cr_0,05S, Ni_0,83Cr_0,17S, Ni_0,75Cr_0,25S. The growing of larger crystals and the mechanism of the transport with AlCl₃ are discussed.

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Cs. Lovász, Teil der Dissertation, Universität Köln 1969.

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K.-H. Bertram, Teil der diplomarbeit, Universität Köln 1970.     

Synthesis of β-ketophosphonates with electron rich β-aryl groups as useful organophosphorus reagents in lignans synthesis

Investigation of the oxidation reaction of electron rich alkoxy substituted β-aryl β-hydroxyphosphonates to corresponding β-ketophosphonates, which may be utilized in syntheses of lignans with various oxidizing agents (PCC, PDC, SIBX, CAN, Oxone^®, KMNO₄/SiO₂, KMnO₄/MS 4 Å, KMnO₄/CuSO₄, KMnO₄/CuSO₄/Al₂O₃, MnO₂, CrO₃/SiO₂, H₂O₂/salen) is described. The effect of oxidants and reaction conditions on the reaction efficiency and yield was also investigated.     

Darstellung und Struktur von BaAl2Se4, BaGa2Se4, CaGa2Se4 und Caln2Te4

Preparation and Crystal Structure of BaAl₂Se₄, BaGa₂Se₄, CaGa₂Se₄, and CaIn₂Te₄ The new compounds BaAl₂Se₄, BaGa₂Se₄, CaGa₂Se₄ and CaIn₃Te₄ crystallize with constants see “Inhaltsübersicht”. The structures are strongly related to the TlSe structure.     

Vapour—liquid equilibrium at elevated pressures from the perturbation theory. II. Binary systems

Vapour—liquid equilibria in binary systems of non-polar non-spherical molecule compounds were studied theoretically by combining the perturbation theory of convex molecule fluids with a new variant of the conformal solution theory. The recently proposed equation of state of hard convex body mixtures and the corresponding expressions for the contact values of distribution functions were employed to determine the reference thermodynamic functions and the perturbation terms. Ten binary systems, i.e. ArCH₄, N₂CH₄, N₂C₂H₄, N₂C₂H₆, CH₄C₂H₄, CH₄C₂H₆, C₂H₄C₂H₆, CO₂C₂H₄, CO₂C₂H₆, and ArCO₂ were studied at constant temperatures. Comparison of theoretical predictions with experimental data is given.     

Probing the Reactivity of the Potent AgF2 Oxidizer. Part 2: Inorganic Compounds

The reactivity of Ag^IIF₂ towards forty two inorganic compounds containing oxo‐ and chloro‐ ligands, has been investigated. Five families of compounds were studied: (i) binary oxides of metals and nonmetals, (ii) ternary salts of inorganic oxo acids, (iii) concentrated or anhydrous oxo‐ acids, (iv) binary and ternary chlorides and (v) oxochlorides. At low temperatures up to 200 °C AgF₂ readily oxidizes HgO, B₂O₃, PbO₂, As₂O₅, Ag₂SO₄, LiBO₂, K₂CO₃, KVO₃, Ag₂WO₄, and AgMnO₄ with concomitant oxygen evolution. In the same conditions V₂O₅, CrO₃, MoO₃, WO₃, CuO, Tl₂O₃, I₂O₅, Re₂O₇, K₂SO₄, HgSO₄, KSO₃F, KNO₃, KClO₄, KIO₄, BaCrO₄, KMnO₄ and KReO₄ resist the action of AgF₂ but many of these compounds get oxidized at higher temperatures (up to nearly 300 °C). Substantial inertness of sulfates, chromates, nitrates, perchlorates, permanganates and perrhenates suggests that one might attempt to synthesize salts of divalent silver with these anions. AgF₂ vigorously reacts with H₂SO₄ (fuming, 30% SO₃), HSO₃Cl (100%), HClO₄ (70%), and HNO₃ (fuming, 100%) at room temperature yielding salts of Ag^I and O₂; for HClO₄ and HNO₃ pre‐cooled to ?35 °C metastable perchlorate / nitrate complexes of Ag^II are obtained. Anhydrous HSO₃F behaves similar to HSO₃CF₃ (see Part 1 of this series) yielding slow methathetical conversion of AgF₂ without concomitant redox reaction. Majority of chlorides and oxochlorides studied (AgCl, AuCl₃, KAuCl₄, WCl₆, WOCl₄, MoOCl₄, MoO₂Cl₂) react with AgF₂ at temperatures below 160 °C. Reaction with SiCl₄ (in contrast to CCl₄) is violent and very exothermic at room temperature. Liquid CrO₂Cl₂ (at room temperature) and solid WO₂Cl₂ (up to 180 °C) are kinetically inert to AgF₂. We do not observe intercalation of AgF₂ with various redox—inert oxo‐ and chloro‐ Lewis bases at the experimental conditions.     

The electronic structures of tetrahedral oxo-complexes. The nature of the “charge transfer” transitions

The electronic structures of MnO^?₄, MnO^2?₄, MnO^3?₄, CrO^2?₄, CrO^3?₄, VO^3?₄, RuO₄, RuO^?₄, RuO^2?₄, TcO^?₄ and MoO^2?₄ have been investigated using the Hartree-Fock-Slater Discrete Variational Method. The calculated ordering of the valence orbitals of all the comlexes is: t₁, 4t₂, 3a₁, 1c, 3t₂, with t₁ the orbital of highest energy. The calculated single transition energies are in good agreement with experimental values and indicate the uniform assignment: t₁ → 2e(v₁), 4t₂ → 2e(v₂). t₁ → 5t₂(v₃), and 4t₂ → 5t₂(v₄). A/D values, calculated from the theory of magnetic circular dichroism (MDC) also support this assignment.Population analyses reveal that all complexes, whether d⁰, d¹ or d², have d-orbital populations close to those of the corresponding M²⁺ ions in which two electrons have been removed from the (n + 1)s orbital of M. This is also true of the excited states, such as t₁ → 2e and 4t₂ → 2e, where a transfer of charge from the ligands to the metal has previously been assumed. It is shown that, instead of a transfer of charge from ligands to metal, electronic excitation consists of a rearrangement of electron density both at the ligands and at the metal.     

Molten lithium sulphate-sodium sulphate—potassium sulphate eutectic. The reactions of six vanadium compounds

The solubilities and thermal stability of six vanadium compounds of oxidation states V, IV and III [i.e., V₂O₅, NaVO₄, Na₃VO₄, VOSO₄, VO₂ and KV(SO₄)₂] have been studied in the ternary eutectic (78 mole % Li₂SO₄, 8.5 mole % Na₂SO₄, 13.5 mole % K₂SO₄) and the products of their reactions with basic, acidic, oxidising and reducing reagents have been identified.     

Zur Reaktion von CF4, CBrF3 und CBr2F2 mit Kieselglas

Reaction of CF₄, CBrF₃, and CBr₂F₂ with Silica CF₄ reacts with silica above 1200 K forming SiF₄ and CO₂. CBrF₃ and CBr₂F₂ yield SiF₄, Br₂, CO₂, and CO as well as products of pyrolysis, such as C₂BrF₅, C₂Br₂F₄, and others. The reaction starts at 900 K (CBrF₃) or 700 K (CBr₂F₂), resp. The CO₂/CO ratio is higher than expected. SiF₄ is absorbed at the surface of silica to a considerable extent.     

Solid phase reactivity of sodium oxosalts of manganese

The observed relationships are presented of the solid phase reactivity of the following salts: NaMnO₄, Na₂MnO₄, Na₃MnO₄, Na₄MnO₄, Na₂MnO₃, Na₂Mn₂O₅, Na₅MnO₄, Na₄Mn₂O₅, NaMnO₂, Na₄MnO₃, Na₂MnO₂ and Na₂Mn₂O₃.     

The electronic structure of molecules by a many-body approach: V. Ionization potentials and one-electron properties of cyclopentadiene and 1-sila-cyclopentadiene-(2,4)

The valence ionization potentials (IP's) of cyclopentadiene and 1-sila-cyclopentadiene-(2,4) are studied by an ab initio many-body approach which includes the effect of electron correlation and reorganization beyond the Hartree-Fock approximation. The Hartree-Fock approximation gives the correct ordering of the IP's for cyclopentadiene but this ordering does not agree with the results of the previous experimental and theoretical studies. The ordering is 1a₂(π), 2b₁(π), 4b₂, 6a₁, 5a₁, 3b₂, 1b₁ (π), 4a₁, 2b₂, 3a₁. For sila-cyclopentadiene the ordering of the IP's is: 1a₂(π), 4b₂, 2b₁(π), 6a₁, 1b₁(π), 5a₁, 3b₂, 4a₁, 3a₁, 2b₂. The Hartree-Fock approximation is found to be incorrect with respect to the ordering of the 4b₂ and 2b₁(π) IP's. A number of one-electron properties are calculated in the one-particle approximation and compared with the available experimental data.     

Gas permeability,diffusivity, solubility,and aging characteristics of 6FDA-durene polyimide membranes

We have determined the intrinsic gas transport properties of He, H₂, O₂, N₂, CH₄, and CO₂ for a 6FDA-durene polyimide as a function of pressure, temperature and aging time. The permeability coefficients of O₂, N₂, CH₄, and CO₂ decrease slightly with increasing pressure. The pressure-dependent diffusion coefficients and solubility coefficients are consistent with the dual-sorption model and partial immobilization. All the gas permeabilities increase with temperature and their apparent activation energies for permeation increase with increasing gas molecular sizes in the order of CO₂, O₂, N₂, and CH₄.The percentages of permeability decay after 280 days of aging are 22, 32, 36, 40, 42, and 30% for He, H₂, O₂, N₂, CH₄, and CO₂, respectively. Interestingly, except for H₂ (kinetic diameter of 2.89 Å), the percentages of permeability decay increase exactly in the order of He (kinetic diameter of 2.6 Å), CO₂ (3.30 Å), O₂ (3.46 Å), N₂ (3.64 Å), and CH₄ (3.80 Å). The apparent activation energies of permeation for O₂, N₂, CH₄, and CO₂ increase with aging because of the increases in activation energies of diffusion and the decreases in solubility coefficients. The activation-energy increase for diffusion is probably due to the decrease in polymeric molar volume because of densification during aging. The reduction in solubility coefficient indicates the available sites for sorption decreasing with aging because of the reduction of microvoids and interstitial chain space.     

Preparation and crystal chemistry of some tetrahedral Li3PO4-type compounds

The crystal chemistry of Li₃PO₄, Li₃VO₄ and Li₃AsO₄ are compared. All three have an isostructural low phase, designated β_II, and an isostructural high phase, γ_II, but in Li₃VO₄ and Li₃AsO₄ the high-low transformation proceeds reversibly through one or more transitional phases some of which can be quenched to ambient. The crystal chemistry of derivative Li₃PO₄ phases, including Li₂MgSiO₄, Li₂ZnSiO₄, Li₂CoSiO₄, Li₂MgGeO₄ and Li₂ZnGeO₄ is compared and the occurrence of high, low, and of distorted high and low phases is correlated with the temperature of preparation and rate of cooling. The derivative Li₃PO₄ phases show extensive or complete mutual solubility not only with each other, but with Li₃PO₄, with M₂XO₄ compounds (M = Zn²⁺, Mg²⁺; X = Ge⁴⁺, Si⁴⁺) and also with Li₄XO₄ compounds (X = Ge⁴⁺, Si⁴⁺). The sequence of phase transformations encountered on heating or cooling is quite sensitive to the stoichiometry of the derivative phases.     

Kryometrische Untersuchungen. IV. Lösungen von oxidischen Mo6+- und Cr6+-Verbindungen in geschmolzenem K2Cr2O7 und KNO3

The depression of freezing point of molten K₂Cr₂O₇ and KNO₃ as solvents was measured after addition of small concentrations of the following compounds: to K₂Cr₂O₇: MoO₃, CrO₃, (NH₄)₂CrO₄, K₂MoO₄, Na₂MoO₄, Li₂MoO₄, and Na₂Mo₂O₇, respectively; to KNO₃: CrO₃, (NH₄)₂Cr₂O₇ K₂Cr₂O₇, K₂CrO₄ and MoO₃, (NH₄)₆(Mo₇O₂₄) · 4 H₂O, K₂Mo₂O₇, K₂MoO₄, Na₂MoO₄ and Li₂MoO₄, respectively. It could be concluded from the measured values of the freezing point depression if a reaction between solvent and solute took place.     

Interaction of salts in ionic melts of the ternary reciprocal systems Na,K‖BO2,MoO4 and Na,K‖BO2,WO4

The phase diagrams of the ternary reciprocal systems Na,K‖BO₂,MoO₄ and Na,K‖BO₂,WO₄ were studied for the first time by a calculation-experimental method and differential thermal analysis. The coordinates were determined for binary eutectics of the diagonal stable sections NaBO₂-K₂MoO₄(K₂WO₄) and the ternary invariant points e(55 mol % NaBO₂, 45 mol % K₂MoO₄, 740°C), e(55 mol % NaBO₂, 45 mol % K₂WO₄, 730°C), E(4.5 mol % NaBO₂, 78 mol % Na₂MoO₄, 17.5 mol % K₂MoO₄, 652°C), E(4.5 mol % NaBO₂, 78 mol % Na₂WO₄, 17.5 mol % K₂WO₄, 643°C), P₂(5 mol % NaBO₂, 56 mol % Na₂MoO₄, 39 mol % K₂MoO₄, 673°C), P₂(5 mol % NaBO₂, 56 mol % Na₂WO₄, 39 mol % K₂WO₄, 671°C). Binary solid solutions based on sodium and potassium metaborates were shown to be stable. Analytical models of phase equilibrium states of the ternary reciprocal systems Na,K‖BO₂,MoO₄(WO₄) were obtained, which enable one to calculate melting (crystallization) points and construct isotherms at any given composition. The specific heats of melting of samples of invariant compositions were found by quantitative differential thermal analysis.     

Energies and Spin States of FeS0/−, FeS20/−, Fe2S20/−, Fe3S40/−, and Fe4S40/− Clusters

The structures and energies of the electronic ground states of the FeS^0/?, FeS₂^0/?, Fe₂S₂^0/?, Fe₃S₄^0/?, and Fe₄S₄^0/? neutral and anionic clusters have been computed systematically with nine computational methods in combination with seven basis sets. The computed adiabatic electronic affinities (AEA) have been compared with available experimental data. Most reasonable agreements between theory and experiment have been found for both hybrid B3LYP and B3PW91 functionals in conjugation with 6‐311+G* and QZVP basis sets. Detailed comparisons between the available experimental and computed AEA data at the B3LYP/6‐311+G* level identified the electronic ground state of ⁵Δ for FeS, ⁴Δ for FeS^?, ⁵B₂ for FeS₂, ⁶A₁ for FeS₂^?, ¹A₁ for Fe₂S₂, ⁸A′ for Fe₂S₂^?, ⁵A′′ for Fe₃S₄, ⁶A′′ for Fe₃S₄^?, ¹A₁ for Fe₄S₄, and ¹A₂ for Fe₄S₄^?. In addition, Fe₂S₂, Fe₃S₄, Fe₃S₄^?, Fe₄S₄, and Fe₄S₄^? are antiferromagnetic at the B3LYP/6‐311+G* level. The magnetic properties are discussed on the basis of natural bond orbital analysis.     

Electrode materials for aqueous rechargeable lithium batteries

In this review, we describe briefly the historical development of aqueous rechargeable lithium batteries, the advantages and challenges associated with the use of aqueous electrolytes in lithium rechargeable battery with an emphasis on the electrochemical performance of various electrode materials. The following materials have been studied as cathode materials: LiMn₂O₄, MnO₂, LiNiO₂, LiCoO₂, LiMnPO₄, LiFePO₄, and anatase TiO₂. Addition of certain additives like TiS₂, TiB₂, CeO₂, etc. is found to increase the performance of MnO₂ cathode. The following materials have been studied as anode materials: VO₂ (B), LiV₃O₈, LiV₂O₅, LiTi₂(PO4)₃, TiP₂O₃, and very recently conducting polymer, polypyrrole (PPy). The cell PPy/LiCoO₂, constructed using polypyrrole as anode delivers an average voltage of 0.86?V with a discharge capacity of 47.7?mA?h?g^?1. It retains the capacity for first 120 cycles. The cell, LiTi₂(PO₄)₃/1?M Li₂SO₄/LiMn₂O₄, delivers a capacity of 40?mA?h?g^?1 and specific energy of 60?mW?h?g^?1 with an output voltage of 1.5?V over 200 charge?Cdischarge cycles. An aqueous lithium cell constructed using MWCNTs/LiMn₂O₄ as cathode material is found to exhibit more than 1,000 cycles with good rate capability.     

Mass spectrometric study of SF6-N2 plasma during etching of silicon and tungsten

The reaction products in the SF₆-N₂ mixture rf plasma during reactive ion etching of Si and W have been measured by a mass spectrometric method. Two kinds of cathode materials were used in this work; they were stainless steel for the Si etching, and SiO₂ for the W etching. The main products detected in the etching experiments of Si and W included SF₄, SF₂, SO₂, SOF₂, SOF₄, SO₂F₂, NSF, NF₃, N₂F₄, N_xS_y, NO₂, and SiF₄. In the W etching with the SiO₂ cathode, additional S₂F₂, N₂O, and WF₆ molecules were also obtained. The formation reactions about the novel NSF compound and the sulfur oxyfuorides were discussed.     

Breaking the Mirror: pH‐Controlled Chirality Generation from a meso Ligand to a Racemic Ligand

To study the conversion from a meso form to a racemic form of tetrahydrofurantetracarboxylic acid (H₄L), seven novel coordination polymers were synthesized by the hydrothermal reaction of Zn(NO₃)₂ ? 6 H₂O with (2S,3S,4R,5R)‐H₄L in the presence of 1,10‐phenanthroline (phen), 2,2′‐bipyridine (2,2′‐bpy), or 4,4′‐bipyridine (4,4′‐bpy): [Zn₂{(2S,3S,4R,5R)‐L}(phen)₂(H₂O)] ? 2 H₂O ( 1 ), [Zn₄{(2S,3R,4R,5R)‐L}{(2S,3S,4S,5R)‐L}(phen)₂(H₂O)₂] ( 2 ), [Zn₂{(2S,3S,4R,5R)‐L}(H₂O)₂] ? H₂O ( 3 ), [Zn₄{(2S,3R,4R,5R)‐L}{(2S,3S,4S,5R)‐L} (2,2′‐bpy)₂(H₂O)₂] ? 2 H₂O ( 4 ), [Zn₂ {(2S,3S,4R,5R)‐L}(2,2′‐bpy)(H₂O)] ( 5 ), [Zn₄{(2S,3R,4R,5R)‐L}{(2S,3S,4S,5R)‐L} (4,4′‐bpy)₂(H₂O)₂] ( 6 ), and [Zn₂ {(2S,3S,4R,5R)‐L}(4,4′‐bpy)(H₂O)] ? 2 H₂O ( 7 ). These complexes were obtained by control of the pH values of reaction mixtures, with an initial of pH 2.0 for 1 , 2.5 for 2 , 4 , and 6 , and 4.5 for 3 , 5 , and 7 , respectively. The expected configuration conversion has been successfully realized during the formation of 2 , 4 , and 6 , and the enantiomers of L, (2S,3R,4R,5R)‐L and (2S,3S,4S,5R)‐L, are trapped in them, whereas L ligands in the other four complexes retain the original meso form, which indicates that such a conversion is possibly pH controlled. Acid‐catalyzed enol–keto tautomerism has been introduced to explain the mechanism of this conversion. Complex 1 features a simple 1D metal–L chain that is extended into a 3D supramolecular structure by π–π packing interactions between phen ligands and hydrogen bonds. Complex 2 has 2D racemic layers that consist of centrosymmetric bimetallic units, and a final 3D supramolecular framework is formed by the interlinking of these layers through π–π packing interactions of phen. Complex 3 is a 3D metal–organic framework (MOF) involving meso‐L ligands, which can be regarded as (4,6)‐connected nets with vertex symbol (4⁵.6)(4⁷.6⁸). Complexes 4 and 5 contain 2D racemic layers and (6,3)‐honeycomb layers, respectively, both of which are combined into 3D supramolecular structures through π–π packing interactions of 2,2′‐bpy. The structure of complex 6 is a 2D network formed by 4,4′‐bpy bridging 1D tubes, which consist of metal atoms and enantiomers of L. These layers are connected through hydrogen bonds to give the final 3D porous supramolecular framework of 6 . Complex 7 is a 3D MOF with novel (3,4,5)‐connected (6³)(4².6⁴)(4².6⁶.8²) topology. The thermal stability of these compounds was also investigated.