Experimentelle Bestimmung der Gleichgewichtslagen im System NaCl(l)-KCl(l)-Na(l)-K(l)

Zusammenfassung Ausgehend von nahezu äquivalenten Mengen an Na und KCl werden die Gleichgewichtszusammensetzungen der metallreichen und der salzreichen Phase des Systems NaCl–KCl–Na–K im Bereich von 1140 bis 1240° K ermittelt. Die Gleichgewichtskonzentrationen der Komponenten werden zur Berechnung der GleichgewichtskonstantenK _x in beiden Phasen herangezogen.

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The equilibrium compositions of both metal-rich and salt-rich phases of the system NaCl–KCl–Na–K are investigated in the temperature range from 1140 to 1240° K, starting from nearly equivalent amounts of Na and KCl. From the experimentally determined concentrations the equilibrium constantsK _x were calculated.

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Phase polymorphism and thermal decomposition of hexadimethylsulphoxidemagnesium(II) chlorate(VII)

Differential scanning calorimetry (DSC) measurements were performed over the temperature range 93–480 K and three enantiotropic (at 323, 409, and 461 K) and one monotropic (at 271 K) phase transitions were detected. Thus, four solid phases (three of them stable and one metastable) and one liquid phase were found. It was concluded, from the entropy change (ΔS) values of these phase transitions that two of them are stable rotational phases and two are crystalline phases (one stable and one metastable). The thermal decomposition of [Mg((CH₃)₂SO)₆](ClO₄)₂, which was studied using thermogravimetry (TG) with simultaneous differential thermal analysis (SDTA), takes place in two main stages. The gaseous products of the decomposition were identified on-line by a quadruple mass spectrometer (QMS). In the first stage, which starts just above ca. 432 K, the compound loses two dimethylsulphoxide (DMSO) molecules per one formula unit. In the second stage (502–673 K) [Mg(DMSO)₄](ClO₄)₂ decomposes explosively and Cl₂, O₂, H₂, and MgSO₄ are finally produced.     

Gas-Phase Structures of Potassium Tetrakis(hexafluoro- acetylacetonato) Lanthanide(III) Complexes [KLn(C5HF6O2)4] (Ln=La,Gd, Lu)

The molecular structures of potassium tetrakis(hexafluoroacetylacetonato)lanthanide(III) complexes [KLn(hfa)₄] (Ln=La, Gd, Lu; hfa=C₅HF₆O₂,) were studied by synchronous gas-phase electron diffraction/mass spectrometry (GED/MS) supported by quantum-chemical (DFT/PBE0) calculations. The compounds sublime congruently and the vapors contain a single molecular species: the heterobinuclear complex [KLn(hfa)₄]. All molecules are of C₁ symmetry with the lanthanide atom in the center of an LnO₈ coordination polyhedron, while the potassium atom is coordinated by three ligands with formation of three K−O and three K−F bonds. One hfa ligand is not bonded to the potassium atom. Topological analysis of the electron-density distributions confirmed the existence of ionic-type K−O and K−F bonding. The structures of the free [KLn(hfa)₄] molecules are compared with those of the related compounds [KDy(hfa)₄] and [KEr(hfa)₄] in their crystalline state. The complex nature of the chemical bonding is discussed on the basis of electron-density topology analyses.     

Synthese und Strukturbestimmung von (i-Pr)2NB(t-BuP)3 und (i-Pr)2NB(t-BuP)4

Synthesis and Structure Analysis of (i-Pr)₂NB(t-BuP)₃ and (i-Pr)₂NB(t-BuP)₄ The diphosphide K(t-Bu)P-(t-BuP)₂-P(t-Bu)K obtained by the cleavage reaction of the 3-membered ring system (i-Pr)₂BN(t-BuP)₂ with potassium reacts with t-BuPCl₂ at ?78°C under ring expansion to form the P₃B ring system (i-Pr)₂NB(t-BuP)₃ – 1,2,3-tri-t-butyl-tri-phospha-4-diisopropyl-aminoboretane ( 1 ). – The 5-membered P₄B ring system (i-Pr)₂NB(t-BuP)₄ – 1,2,3,4-tetra-t-butyl-tetraphospha-5-diisopropylaminoborolidine, ( 2 ) – is formed from K(t-Bu)P? (t-BuP)₂? P(t-Bu)K and (i-Pr)₂NBCl₂ analogous to the above reaction. 1 and 2 could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analysis. 1 shows at 200 K two conformation isomers; for 2 ³¹P-^10,11B-isotopic shifts could be identified.     

Physico-chemical studies on thermal analysis of cobalt hexa(formato)ferrate(III) decahydrate

Thermal decomposition of cobalt hexa(formato)ferrate(III) decahydrate, Co₃[Fe(HCOO)₆]₂. 10H₂O, has been studied up to 973 K in static air atmosphere, employing TG, DTG, DSC, XRD, ESR, Mössbauer and infrared spectroscopic techniques. Dehydration occurs in two stages in the temperature range of 340–430 K. Immediately after the removal of the last water molecule the anhydrous complex undergoes decomposition till α-Fe₂O₃ and cobalt carbonate are formed at 588 K. In the final stage of remixing of cations, a solid state reaction between α-Fe₂O₃ and cobalt carbonate leads to the formation of CoFe₂O₄ at a temperature (953 K) much lower than for the ceramic method. A saturation magnetization value of 2310 Gauss of ferrite (CoFe₂O₄) shows its potential to function at high frequencies.     

Synthesis and crystal structure of hexakis(isothiocyanato)erbium(III) thiocyanate bis(18-crown-6)dipotassium bis[(18-crown-6)ethanolpotassium]

A new complex compound, [K₂(18-crown-6)₂[K(18-crown-6)(EtOH)]₂[Er(NCS)₆](SCN) (I), was synthesized and its crystal structure was studied by X-ray diffraction. In this work, the synthes and X-ray difraction stady of the crystals of a new complex, hexakis (isothiocyanato) erbiu(III) thiocyanate bis(18-crown-6) dipotassium bis(18-crown-6) ethanolpotassium], [K₂(18-crown-6)₂][K(18-crown-6)(ETON)]₂[Er(NCS)₆(SCN)(I)] are described. In crystal I, the alternating [Er(NCS)₆]^3? anions and binuclear complex cation [K(18-crown-6)₂]²⁺ from infinite chains via the F-S bonds, while two complex cations [K(18-crown-6)(ETON)]⁺ and the statistically disordered SCN^? anion between them are linked by the hydragen bonds O-H…S and O-H…N. Complex I contains the host-guest complex cations [K₂(18-crown-6)₂)]²⁺ and [K(18-crown-6)(ETON)]⁺ [1]. The alternating octabedral [Er(NCS)₆]^3? anions and binuclear complex cations [K₂(18-crown-6)₂]²⁺of crystal I form infinite chains via the K-S bonds, while two complex cations [K(18-crown-6)(EtOH)]⁺ and the statistically disordered SCN^? anion lying between them are linked by interionic hydrogen bonds O-H…S and O-H…N. Complex I contains the host-guest complex cations [K₂(18-crown-6)₂]²⁺ and [K(18-crown-6)(EtOH)]⁺ [1].     

Manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes with 4-oxo-4H-1-benzopyran-3-carboxaldehyde

The complexes Mn(II), Co(II), Ni(II) and Zn(II) with 4-oxo-4H-1-benzopyran-3-carboxaldehyde were synthesized and characterized by elemental analysis, infrared and UV spectroscopy, X-ray diffraction patterns, magnetic susceptibility, thermal gravimetric analysis, conductivity and also solubility measurements in water, methanol and DMF solution at 298 K. They are polycrystalline compounds with various formula and different ratio of metal ion:ligand. Their formula are following: [MnL₂(H₂O)](NO₃)₂·2H₂O, [CoL₂](NO₃)₂·3H₂O, [NiL₂](NO₃)₂·3H₂O, [CuL₂](NO₃)₂·H₂O and [ZnL₃](NO₃)₂, where L = C₁₀H₆O₃. The coordination of metal ions is through oxygen atoms present in 4-position of γ-pyrone ring and of aldehyde group of ligand. Chelates of Mn(II), Co(II), Ni(II) and Cu(II) obey Curie–Weiss law and they are high-spin complexes with the weak ligand fields. The thermal stability of analyzed complexes was studied in air at 293–1,173 K. On the basis of the thermoanalytical curves, it appears that thermal stability of anhydrous analysed chelates changed following: Cu (423 K) < Zn (438 K) ~ Co (440 K) < Ni (468 K). The gaseous products of thermal decomposition of those compounds in air atmosphere are following: CO₂, CO, NO₂, N₂O, hydrocarbons and in case of hydrates also water. The molar conductance data confirm that the all studied complexes are 1:2 electrolytes in DMF solution.     

Bis(tetraphenylcyclobutadien)palladium(0)

Tetraphenylcyclobutadienepalladium dichloride reacts with 1,2,3,4-tetraphenyl-1,4-dilithiumbutadiene or with sodium with abstraction of halide to give the sandwich compound bis(tetraphenylcyclobutadiene)palladium(0). The structure of the latter is elucidated by spectroscopic methods and its reactions with Br₂, H₂, K and HNO₃ are described.     

Darstellung,Charakterisierung und Reaktionsverhalten von Natrium‐ und Kaliumhydridosilylamiden R2(H)Si—N(M)R′ (M = Na,K) — Kristallstruktur von [(Me3C)2(H)Si—N(K)SiMe3]2·THF

Preparation, Characterization and Reaction Behaviour of Sodium and Potassium Hydridosilylamides R₂(H)Si—N(M)R′ (M = Na, K) — Crystal Structure of [(Me₃C)₂(H)Si—N(K)SiMe₃]₂ · THF The alkali metal hydridosilylamides R₂(H)Si—N(M)R′ 1a‐Na — 1d—Na and 1a‐K — 1d‐K ( a : R = Me, R′ = CMe₃; b : R = Me, R′ = SiMe₃; c : R = Me, R′ = Si(H)Me₂; d : R = CMe₃, R′= SiMe₃) have been prepared by reaction of the corresponding hydridosilylamines 1a — 1d with alkali metal M (M = Na, K) in presence of styrene or with alkali metal hydrides MH (M = Na, K). With NaNH₂ in toluene Me₂(H)Si—NHCMe₃ ( 1a ) reacted not under metalation but under nucleophilic substitution of the H(Si) atom to give Me₂(NaNH)Si—NHCMe₃ ( 5 ). In the reaction of Me₂(H)Si—NHSiMe₃ ( 1b ) with NaNH₂ intoluene a mixture of Me₂(NaNH)Si—NHSiMe₃ and Me₂(H)Si—N(Na)SiMe₃ ( 1b‐Na ) was obtained. The hydridosilylamides have been characterized spectroscopically. The spectroscopic data of these amides and of the corresponding lithium derivatives are discussed. The ²⁹Si‐NMR‐chemical shifts and the ²⁹Si—¹H coupling constants of homologous alkali metal hydridosilylamides R₂(H)Si—N(M)R′ (M = Li, Na, K) are depending on the alkali metal. With increasing of the ionic character of the M—N bond M = K > Na > Li the ²⁹Si‐NMR‐signals are shifted upfield and the ²⁹Si—¹H coupling constants except for compounds (Me₃C)(H)Si—N(M)SiMe₃ are decreased. The reaction behaviour of the amides 1a‐Na — 1c‐Na and 1a‐K — 1c‐K was investigated toward chlorotrimethylsilane in tetrahydrofuran (THF) and in n‐pentane. In THF the amides produced just like the analogous lithium amides the corresponding N‐silylation products Me₂(H)Si—N(SiMe₃)R′ ( 2a — 2c ) in high yields. The reaction of the sodium amides with chlorotrimethylsilane in nonpolar solvent n‐pentane produced from 1a‐Na the cyclodisilazane [Me₂Si—NCMe₃]₂ ( 8a ), from 1b‐Na and 1‐Na mixtures of cyclodisilazane [Me₂Si—NR′]₂ ( 8b , 8c ) and N‐silylation product 2b , 2c . In contrast to 1b‐Na and 1c‐Na and to the analogous lithium amides the reaction of 1b‐K and 1c‐K with chlorotrimethylsilane afforded the N‐silylation products Me₂(H)Si—N(SiMe₃)R′ ( 2b , 2c ) in high yields. The amide [(Me₃C)₂(H)Si—N(K)SiMe₃]₂·THF ( 9 ) crystallizes in the space group C2/c with Z = 4. The central part of the molecule is a planar four‐membered K₂N₂ ring. One potassium atom is coordinated by two nitrogen atoms and the other one by two nitrogen atoms and one oxygen atom. Furthermore K···H(Si) and K···CH₃ contacts exist in 9 . The K—N distances in the K₂N₂ ring differ marginally.     

Gas permeability of cardo-poly(ether-ether-ketone) and poly(phenylene sulfide)

The gas permeability and sorption of CO₂ and N₂O was measured on cardo-poly(ether-ether-ketone) (C-PEEK) and poly(phenylene sulfide) (PPS) at 298 K. The results are discussed on the basis of the dual-mode model. Results obtained from measurements at 308 K are compared with literature data of poly(phenylene oxide) (PPO), poly(sulfone) (PSU) and poly(carbonate) (PC). While C-PEEK shows similar transport properties as PC and PSU, the values of PPS are distinctly lower. The solubility of CO₂ in the various polymers as well as the correlation of the permeability coefficients of the same polymers for He, Ar, CO₂, N₂, and CH₄ with the kinetic molecular diameter of the gases indicate a simple relation of the transport properties with the polymer density.     

Low-temperature specific heat of the cluster compound Au55 (P(C6H5)3)12Cl6

Specific-heat measurements on the cluster compound Au₅₅(P(C₆H₅)₃)₁₂Cl₆ at temperatures 0.06 K ≤T≤3 K and in magnetic fields 0≤B≤6 T are reported. While above 0.6 K the specific heatC is dominated by the inter-cluster vibrational contribution observed previously, an anomalous increase ofC towards lowT is observed below 0.3 K, withC ～T ^?2. This contribution develops into a Schottky-like anomaly forB≥0.4 T, indicating that it might be attributed to local moments which are also observed in ESR measurements. From the height of the anomaly one can infer that approximately one tenth of the Au₅₅ clusters carry a magnetic moment. For 0.6 K≤T≤1 K andB=0 our data indicate the absence of a linear electronic specific-heat contribution expected for bulk Au. This possibly constitutes the first direct observation of the quantum-size effect on electronic energy levels in the specific heat.     

Phase polymorphism of [Ni(DMSO)6](BF4)2 studied by differential scanning calorimetry

The tetrafluoroborate of hexadimethylsulfoxidenickel(II) was synthesized and studied by differential scanning calorimetry. Seven solid phases of [Ni(DMSO)₆](BF₄)₂ were revealed. Specifically, six phase transitions of the first order were detected between the following solid phases: stable KIb → stable KIa at T _C6 = 335 K, metastable KIIb → metastable KIIa at T _C5 = 368 K, metastable KIII → overcooled phase KI at T _C4 = 378 K, metastable KIIa → overcooled phase KI at T _C3 = 396 K, stable KIa → stable KI at T _C2 = 415 K and stable KI → stable K0 at T _C1 = 433 K. [Ni(DMSO)₆](BF₄)₂ begins decomposition at 440 K with loss of one DMSO molecule per formula unit forming [Ni(DMSO)₅](BF₄)₂ (phase L0) which melts next in two steps in the temperature range 550–593 K. From the entropy changes connected both with melting and with phase transitions, it can be concluded that phases KI, overcooled KI and K0 are orientationally dynamically disordered (ODIC) crystals. Stable phases KIb, KIa and metastable phase KIII are ordered solid phases. Metastable phase KIIa and metastable phase KIIb are more or less ordered solid phases.     

Physico-chemical studies on thermal analysis of cobalt hexa(formato)ferrate(III) decahydrate

Thermal decomposition of cobalt hexa(formato)ferrate(III) decahydrate, Co₃[Fe(HCOO)₆]₂. 10H₂O, has been studied up to 973 K in static air atmosphere, employing TG, DTG, DSC, XRD, ESR, Mössbauer and infrared spectroscopic techniques. Dehydration occurs in two stages in the temperature range of 340–430 K. Immediately after the removal of the last water molecule the anhydrous complex undergoes decomposition till -Fe₂O₃ and cobalt carbonate are formed at 588 K. In the final stage of remixing of cations, a solid state reaction between -Fe₂O₃ and cobalt carbonate leads to the formation of CoFe₂O₄ at a temperature (953 K) much lower than for the ceramic method. A saturation magnetization value of 2310 Gauss of ferrite (CoFe₂O₄) shows its potential to function at high frequencies.     

New complexes of gold(III) with pseudohalides. I. The Synthesis and Properties of Potassium Dicyanodiazidoaurate(III)

The compound K[Au(CN)₂(N₃)₂] was synthetised starting from K[Au(CN)₂Cl₂] and KN₃. The composition of the new complex ion was established spectrophotometrically, by the mole ratio method. The spectra, in visible, UV and IR domains are discussed. Some properties of the compound are also described.     

Electronic structure of solid state tris(1,3-diphenyl-1,3-propanedionato)aquoeuropium(III)

Single crystal orthoaxial absorption spectra are reported for tris(1,3-diphenyl-1,2-propanedionato)aquoeuropium(III) at ambient temperature and 77 K. The hypersensitive ⁷F_o→⁵D₂ and magnetic/electric dipole forbidden ⁷F_o→⁵D_o transitions are found to be unusually intense. Polarizations and absolute oscillator strengths are determined for all observed transitions from the ground state at 77 K.     

Collisional Deactivation of K(7s2S) and K(5d2D) by No

Radiative lifetimes and total deactivation cross sections of K(7²S) and K(5²D) by collision with NO are studied. The K atomic vapor in either the 7²S or the 5²D state was prepared by two- photon absorption using a dye laser. The decay signal of the time-resolved fluorescence from the 7²S – 4²P_1/2 or 5²D – 4²P_3/2 transition was then monitored. Based on a Stern-Volmer analysis, the radiative lifetimes are 155 ±8 ns and 561 ± 18 ns for the K(7²S) and K(5²D) states, respectively. The total deactivation cross sections are 88 ±1Ų and 70 ±2Ų for the K(7²S)-NO and K(5₂D)-NO collisions, respectively. In the absence of NO collisions the radiative lifetimes obtained in this work show excellent agreement with those previously reported. The quenching cross sections for NO have been measured for the first time, and have values in a reasonable range, when compared with Na-N₂ collisions.     

Astatistical aspects of the stabilities of ternary complexes of cobalt(II), nickel(II), copper(II) and zinc(II) involving aminopolycarboxylic acids and heteroaromaticN-bases as primary ligands and acetohydroxamic acid as a secondary ligand

Summary Stability constants of binary (ML, ML₂) and ternary (MAL) complexes [M=Co^II, Ni^II, Cu^II or Zn^II; A=iminodiacetic acid (ida),N-methyliminodiacetic acid (Me-ida), anthranilatediacetic acid (ada), nitrilotriacetic acid (nta), 2,2-bipyridine (bipy), orthophenanthroline (o-phen); HL =acetohydroxamic acid] have been determined at 25°C at an ionic strength of 0.1M KNO₃ by the Iriving Rossotti technique. In the case of aminopolycarboxylic acids as primary ligands, there is always a lowering of K _MAL ^MA from K _ML ^M and K ₂ ^ML while in the case of heteroaromaticN-bases as primary ligands, the values of K _MAL ^MA are very close to those of K _ML ^M . In the ternary systems studied, the values of K _MAL ^MA are in the sequence, K _M(o-phen) ^M(o-phen) >K _M(bipy)L ^M(bipy) K _M(ida)L ^M(ida) >K _M(Me-ida)L ^M(Me-ida) >K _M(nta)L ^M(nta) >K _M(ada)L ^M(ada) , while in the case of Cu^II, the values of M _M(nta)L ^M(nta) and K _M(ada)L ^M(ada) are drastically reduced compared to all other primary ligands. For aminopolycarboxylic acids, the sequence of K _MAL ^MA is opposite to those of K _MA ^M and K _MAL ^M though in the sequence of K _MA ^M , K _MAL ^M and K _MAL ^MA for A=ada and nta their relative positions are unaltered. The obtained results are explained in the light of different astatistical factors such as electrostatic effects, steric hindrance, change of effective positive charge on the central metal depending upon the -basic and -acidic character of the primary ligands.     

Synthesis and characterization oftrans-dihalogeno(isonitrosoketonato) (isonitrosoketone)osmium(III)

Summary Reaction of [OsX₆]^2– (X = Cl or Br) with HK [HK = PhC(=O)C(=NOH)R; R=H, Me or Ph] yielded osmium(III) complexes of the type [OsX₂(K)(HK)]. The OsX₂ group wastrans and the hydrogen-bonded (K)(HK) moiety behaved as a planar tetradentate N₂O₂ chelator. The complexes were one-electron paramagnets and exhibited characteristic osmium(III) e.p.r. spectra. Several spin-allowed and spin-forbidden charge-transfer transitions were observed in the 200–1300 nm region.     

Low-Temperature Heat Capacities of Terbium Molybdate Phosphates M 2 I Tb(MoO4)(PO4) (MI = Na or K)

The heat capacities of Na₂Tb(MoO₄)(PO₄) and K₂Tb(MoO₄)(PO₄) were measured by adiabatic calorimetry at low temperatures (6.34–333.74 and 7.20–341.17 K, respectively). Smoothed thermal-capacities values were used to calculate the entropy, enthalpy increments, and reduced Gibbs energy. The respective values at 298.15 K are as follows: for Na₂Tb(MoO₄)(PO₄), C _p ⁰ (298.15 K) = 240.1 ± 0.2 J/(K mol), ⁰ (298.15 K) = 307.4 ± 0.4 J/(K mol), H ⁰(298.15 K) ? H ⁰(0) = 44.95 ± 0.03 kJ/mol, and Φ⁰(298.15 K) = 156.6 ± 0.5 J/(K mol); and for K₂Tb(MoO₄)(PO₄): C _p ⁰ (298.15 K) = 245.1 ± 0.1 J/(K mol), S ⁰(298.15 K) = 322.9 ± 0.1 J/(K mol), H ⁰(298.15 K) ? H ⁰(0) = 46.58 ± 0.02 kJ/mol, and Φ⁰(298.15 K) = 166.6 ± 0.2 J/(K mol). The noncooperative magnetic component of the heat capacity was estimated.     

Biological Properties of Antimony(III) Fluoride Complexes

Result of a study of how antimony trifluoride and fluoride complexes MSb₂F₇ (M = K, Rb, Cs, Tl, NH₄), MSbF₄ (M = Na, K, Rb, Cs, NH₄), and M₂SbF₅ (M = Na, K, Rb, Cs, Tl, NH₄) affect the growth of associations of marine bacteria and vital activity of marine alga Ulva Fenestrata are presented. The possible ways of using Sb(III) fluoride compounds are discussed.