Beiträge zur Chemie der Oxidhalogenide von Molybdän und Wolfram. V. Molybdänoxidtetrachlorid und Molybdänoxidtrichlorid

The formation enthalpies were ascertained from the solution enthalpies in 2 n NaOH resp. 2 n NaOH + 1% H₂O₂. The results of equilibrium measurements in the systems give the formation enthalpies and standard entropies: . The value of the standard entropy of the gaseous MoOCl₄ was estimated to be 91 (±3) cl. From the enthalpies and entropies of sublimation the values were obtained.     

Der Sublimationsdruck von NbOCl3,f und die Normalentropie von NbOCl3,g

Sublimation Pressure of NbOCl_3,s and Standard Entropy of NbOCl_3,g The sublimation pressure of NbOCl₃ has been measured by means of the transportation method. The carrier-gas contained NbCl₅, so that the decomposition of NbOCl₃ is prevented: . Further at 1277 K the reaction Nb₂O₅ + 3 Cl₂ = 2 NbOCl_3,g + 1.5 O₂ has been measured by means of the transportation method. Considering ΔCp and ΔH°(298) follows .     

Beiträge zum thermischen Verhalten von Oxoniobaten der Übergangsmetalle. IV. Zum Chemischen Transport von CoNb2O6 mit Cl2, NH4 und HgCl2. Experimente und Modellrechnungen

Contributions on the Thermal Behaviour of Oxoniobates of the Transition Metals. IV The Chemical Vapour Transport of CoNb₂O₆ with Cl₂, NH₄Cl, or HgCl₂. Experiments and Calculations Well shaped crystals of CoNb₂O₆ were obtained by CVT using Cl₂ (added as PtCl₂), NH₄Cl or HgCl₂ as transport agents (1020°C → 960°C). As a result of thermodynamic calculations the evaporation and deposition of CoNb₂O₆ in the presence of Cl₂ can be expressed by the heterogenous endothermic equilibrium (1). The endothermic reaction (2) is responsible for the CVT of CoNb₂O₆ if NH₄Cl is used as transport agent: The unfavourable site of the equilibrium (3) causes the small transport effect using HgCl₂ as transport agent. Assuming Δ_BH°₂₉₈(CoNb₂O_6,s) = ?524.7 kcal/mol a satisfying agreement between thermodynamical calculation and experimental results can be reached.     

Die Sublimation und thermische Zersetzung von TeJ4 und die Existenz von TeJ2 in der Gasphase

The Sublimation and the Thermal Decomposition of TeJ₄ and the Existence of TeJ₂ in the Gaseous Phase The sublimation and the decomposition of TeJ₄ have been investigated. For the sublimation and the decomposition reactions and the values of enthalpy and entropy were derived (see ?Inhaltsübersicht”?). The existence of TeJ₂ in the gaseous phase was demonstrated by equilibrium measurements and chemical transport experiments.     

Der Sättigungsdruck von NbBr5 und Tal5

Sublimation Pressure of NbBr₅, NbI₅, and TaI₅ The sublimation pressure of NbBr₅, NbI₅ and TaI₅ has been determined by a spectralphotometric method: . The vapour pressure of NbI_5,1 is equal to log \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\,{\rm = }\, - \frac{{4653}}{{\rm T}}\, + \,5.43 $\end{document}. All the pressure are given in atm. The melting point of NbI₅ is 673 ± 1 K.     

Beiträge zum thermischen Verhalten von Oxoniobaten der Übergangsmetalle. V. Zum Chemischen Transport von NiNb2O6 mit Cl2 und NH4Cl. Experimente und Modellrechnungen

Contributions on the Thermal Behaviour of Oxoniobates of the Transition Metals. V. Chemical Vapour Transport of NiNb₂O₆ with Cl₂ or NH₄Cl. Experiments and Calculations Well shaped crystals of NiNb₂O₆ were obtained by CVT using Cl₂ (added as PtCl₂) or NH₄Cl as transport agents (1020°C → 960°C). As a result of thermodynamic calculations the migration of NiNb₂O₆ in the temperature gradient in the presence of Cl₂ can be expressed by the heterogenous endothermic equilibrium (1). Assuming Δ_BH(NiNb₂O_{6, s}) = ?524.4 kcal/mol a satisfying agreement between thermodynamical calculation and experimental results can be reached. NH₄Cl is less suitable as transport agent, because Ni²⁺ is partly reduced to the metal by NH₃. The additionally H₂O produced by this reduction leads to a less favourable equilibrium position of (2) and to low deposition rates. .     

Zum chemischen Transport von CrOCl und Cr2O3 — Experimente und Modellrechnungen zur Beteiligung von CrOCl2,g

On the Chemical Transport of CrOCl and Cr₂O₃ - Experiments and Model Calculations for Participation of CrOCl_2,g . The migration of CrOCl in a temperature gradient (600°C→500°C) in the presence of chlorine is a result from an endothermic reaction . Above T₂ = 900°C several reactions are super imposed and Cr₂O₃, the product of the decomposition of CrOCl, migrates following the endothermic reaction . By continously monitoring the mass changes during the complete duration of the experiment the consecutive stationary deposition reactions could be registered separately and nonstationary changes in the gasphase could be recognized. The observed decomposition of solid CrOCl into Cr₂O_3,s as well as CrCl_3,g under equilibrium conditions is in accordance with thermochemical calculations assuming the heat of formation of CrOCl to be Δ_BH = - 135.3 ± 2 [kcal/mol]. Using this value the chemical transport of CrOCl with Cl₂, HCl, and HgCl₂ can be described.     

Zur Thermodynamik der Metallcarbonate 3. Mitteilung [1]. Löslichkeitskonstanten und Freie Bildungsenthalpien von ZnCO3 und Zn5(OH)6(CO3)2 bei 25°

The solubilities of ZnCO₃ and Zn₅(OH)₆(CO₃)₂ have been investigated at 25°C in solutions of the constant ionic strength 0,2 M consisting primarily of sodium perchlorate. From experimental data the following values for equilibrium constants and GIBBS free energies of formation are deduced: A predominance area diagram for the ternary system Zn²⁺–H₂O–CO_2(g) including ZnO, ZnCO₃, Zn₅(OH)₆(CO₃₎₂, and Zn²⁺ is given.     

Zintlphasen mit isolierten SiAs4- bzw. GeAs4-Anionen: Darstellung und Struktur von Ba4SiAs4 und Ba4GeAs4 sowie Sr4SiAs4 und Sr4GeAs4

Die erstmals dargestellten isotypen Verbindungen Ba₄SiAs₄, Ba₄GeAs₄, Sr₄SiAs₄ und Sr₄GeAs₄ kristallisieren kubisch, Raumgruppe P4 3n, mit 8 Formeleinheiten in der Elementarzelle: In den Strukturen liegen isolierte, d.h. nur von Ba-Ionen umgebene SiAs - bzw. GeAs -Tetraeder vor. Die Verbindungen sind die bisher eindrucksvollsten Beispiele für Zintlphasen mit komplexen Anionen. Zintl Phases with Isolated SiAs₄ or GeAs₄ Anions: Preparation and Structure of Ba₄SiAs₄, Ba₄GeAs₄, Sr₄SiAs₄, and Sr₄GeAs₄ The new compounds Ba₄SiAs₄, Ba₄GeAs₄, Sr₄SiAs₄, and Sr₄GeAs₄ have been prepared and their structures determined. They crystallize in the cubic system, P4 3n, with axes: data see “Inhaltsübersicht”. There are isolated SiAs or GeAs tetrahedra in the structures. The compounds can be interpreted as Zintl phases with complex anions.     

Trägerfixierte Organometallkomplexe. VI. Charakterisierung und Reaktivität Polysiloxan-gebundener (Ether-phosphan)ruthenium(II)-Komplexe

Supported Organometallic Complexes. VI. Characterization und Reactivity of Polysiloxane-Bound (Ether-phosphane)ruthenium(II) Complexes The ligands PhP(R)CH₂D [R = (CH₃O)₃Si(CH₂)₃; D = CH₂OCH₃ ( 1b ); D = tetrahydrofuryl ( 1c ); D = 1,4-dioxanyl ( 1d )] have been used to synthesize (ether-phosphane)ruthenium(II) complexes, which have been copolymerized with Si(OEt)₄ to yield polysiloxane-bound complexes. The monomers cis,cis,trans-Cl₂Ru(CO)₂(P ～ O)₂ ( 3b ) and HRuCl(CO)(P ～ O)₃ ( 5b ) were treated with NaBH₄ to form cis,cis,trans-H₂Ru(CO)₂(P ～ O)₂ ( 4b ) and H₂Ru(CO)(P ～ O)₃ ( 6b ), respectively (P ～ O = η¹-P coordinated; = η²- coordinated). Addition of Si(OEt)₄ and water leads to a base catalyzed hydrolysis of the silicon alkoxy-functions and a precipitation of the immobilized counterparts 4b ′, 6b ′. The polysiloxane matrix resulting by this new sol gel route has been described under quantitative aspects by ²⁹Si CP-MAS NMR spectroscopy. 4b ′ reacts with carbon monoxide to form Ru(CO)₃(P ～ O)₂ ( 7b ′). Chelated polysiloxane-bound complexes Cl₂Ru( )₂ ( 9c ′, d ′) and Cl₂Ru( )(P ～ O)₂ ( 10b ′, c ′) have been synthesized by the reaction of 1b–c with Cl₂Ru(PPh₃)₃ ( 8 ) followed by a copolymerization with Si(OEt)₄. The polysiloxane-bound complexes 9c ′, d ′ and 10b ′, c ′ react with one equivalent of CO to give Cl₂Ru(CO)( )(P ～ O) ( 12b ′– d ′). Excess CO leads to the all-trans-complexes Cl₂Ru(CO)₂(P ～ O)₂ ( 14b ′– d ′), which are thermally isomerized to cis,cis,trans- 3b ′– d ′. The chemical shift anisotropy of ³¹P in crystalline Cl₂Ru( )₂ ( 9a , R = Ph, D = CH₂OCH₃) has been compared with polysiloxane-bound 9d ′ indicating a non-rigid behavior of the complexes in the matrix.     

Über Chalkogenolate. 82 [1]. N-Hydroxycarbamate und Ester der N-Hydroxycarbamidsäure und -carbimidsäure

On Chalcogenolates. 82. N-Hydroxy Carbamates and Esters of N-Hydroxy Carbamic Acid and Carbamic Acid The reaction between hydroxylammonium chloride, CO₂, and the corresponding hydroxide leads to N-hydroxy carbamates Esters of N-hydroxy carbamic acid have been prepared by reaction of N-hydroxy carbamates with alkyl bromide. – At room temperature the ethyl ester decomposes and forms the ester of N-hydroxy carbimic acid HO? N?C(OC₂H₅)₂. The prepared compounds have been characterized by different methods.     

Über Chalkogenolate. 79. Untersuchungen über N-Hydroxydithiocarbamidsäure 1. Darstellung und Eigenschaften von N-Hydroxydithiocarbamaten und von Hydroxylammoniumdithiocarbamat

On Chalcogenolates. 79. Studies on N-Hydroxy Dithiocarbamic Acid. 1. Preparation and Properties of N-Hydroxy Dithiocarbamates and of Hydroxylammonium Dithiocarbamate In the presence of the corresponding hydroxide the reactions between hydroxylamine and carbon disulfide lead to N-hydroxy dithiocarbamates and [H₃NOH][S₂C? NH₂], respectively. The unstable compounds have been characterized by different methods.     

Zur Kenntnis der Chemie der Metallcarbonyle und der Cyanokomplexe in flüssigem Ammoniak. XXXI. Über die Reaktionen von kationischen η5-Cyclopentadienylmolybdäncarbonyl-Komplexen mit flüssigem Ammoniak

The Chemistry of Metal Carbonyls and Cyano Complexes in Liquid Ammonia. XXXI. On the Reactions of Cationic η⁵-Cyclopentadienyl-molybdenumcarbonyl Complexes with Liquid Ammonia Depending on the reaction conditions, the cationic complexes [η⁵-C₅H₅Mo(CO)₃L]⁺ (L = NH₃, PPh₃, CO) react with liquid ammonia according to: The characteristics and reactivities of the new carbomoyl derivatives are described.     

Gasförmige Komplexe von Trichloriden,Tetrachloriden und Pentachloriden mit Aluminiumchlorid

Gaseous Complexes of Trichlorides, Tetrachlorides, and Pentachlorides with Aluminium Chloride The equilibria have been determined with the solid chlorides TiCl₃, VCl₃, ScCl₃, NdCl₃, ZrCl₄, TaCl₅, (NbCl₅) (double cells which contain AlCl₃ and MCl_x respectively; mass spectrometer). The complexes contain 1 AlCl₃/MCl_x. ZrAl₂Cl₁₀ molecules also have been observed. With MoCl₃ and WCl₆ AlCl₃ complexes could not be found. The ΔHº and ΔSº values have been discussed in connection with literature data. Complexes containing more as 1 AlCl₃/LnCl₃ (Ln ? Nd, Sm, Gd) also are included in the discussion.     

Der Sättigungsdruck von NbCl4 und NbBr4

Vapour Pressure of NbCl₄ and NbBr₄ The vapour pressur of solid NbCl₄ has been determined spectralphotometrically near 600 K: . NbCl₄ is monomolecular in the gaseous state. In the same way the vapour pressure of NbBr₄ has been found: .     

Über Chalkogenolate. 99. Untersuchungen über Monothiocarbamidsäure 1. Darstellung und Eigenschaften von Monothiocarbamaten

On Chalcogenolates. 99. Studies on Monothiocarbamic Acid. 1. Synthesis and Properties of Monothiocarbamates The monothiocarbamates , and Ba[SOC? NH₂]₂ have been prepared and characterized by means of infrared, electron absorption, and mass spectra. The existence of the free monothiocarbamic acid was ascertained.     

Über Chalkogenolate. 121. Untersuchungen über N-Cyanomonothiocarbimidsäure 1. Darstellung und Eigenschaften von Alkalimetall-N-cyanomonothiocarbimaten

On Chalcogenolates. 121. Studies on N-Cyanomonothiocarbimic Acid. 1. Synthesis and Properties of Alkali Metal N-Cyanomonothiocarbimates The hitherto unknown N-cyanomonothiocarbimates M₂[SOC?N? CN] · H₂O, where M = Na, K, Rb, Cs, have been prepared by reaction of the corresponding alkali metal salt of cyanamide with COS. N-Cyanomonothiocarbimates react with sulfur to form the ion, which gives with an acid and with CH₃I the methyl compound . The reaction of the latter compound with H₂O₂ yields . All compounds have been characterized by means of diverse methods.     

Beiträge zur Komplexchemie der Phosphine und Phosphinoxide,XXVIII. Übergangsmetall-aminoalkylphosphin-Komplexe Teil 2: Palladium- Und Platinkomplexe

On the Coordination Chemistry of Phosphines and Phosphine Oxides. XXVIII. Transition Metal Aminoalkylphosphine Complexes. Part II: Palladium and Platinum Complexes Aminoalkylphosphines – C₆H₅HP? CH₂ · CH₂? , (C₆H₅)₂P? CH₂ · CH₂ · CH₂? NH₂, (C₆H₅)₂P? CH₂ · CH₂ · CH₂? N?CHC₆H₅ – react with palladium and platinum salts to give coordination compounds of the type MX₂, MX₂()₂, and MX₂()₄ (M = Pd, Pt; X = Cl, BPh₄). The chelating activity of the ligands, structure and properties of the metal complexes are discussed.     

Zur Kenntnis der Organophosphorverbindungen. XV. Darstellung und Reaktionen von Trimethylsilylestern der Phosphinsäuren

On Organophosphorus Compounds. XV. Preparation and Reactions of Trimethylsilyl Esters of Phosphinic Acids Trimethylsilylesters of Phosphinic acids R₂P(X)YSi(CH₃)₃ (R ? CH₃, C₂H₅, C₃H₇, t?C₄H₉, C₆H₅; X, Y ? O, S) were prepared by 7 different methods as in some cases easily hydrolysable but thermally remarkably stable compounds. The properties and some reactions of these substances are reported, their structures confirmed by IR? as well as ¹H- and ³¹P-NMR-spectroscopy. Dimethylsilylen-bis(phosphinic acid esters) were obtained according to \documentclass{article}\pagestyle{empty}\begin{document}$ 2{\rm R}_{2} {\rm P(\rm X)\rm ONH}_{4} + {\rm R}_{\rm 2} {\rm SiCl}_{2} \to 2{\rm E NH}_{4} {\rm Cl + R}_{2} {\rm P(X) - O - SiR}_{2} - {\rm O - P(X)R}_{2} ({\rm R = CH}_{3};{\rm X = O,S}) $\end{document}.     

Stable γ-distonic oxonium ions: R\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm O}\limits^ + $\end{document}HCHR′ĊH2CHR″ and their characteristic reaction

The γ-distonic radical ions R$ \mathop {\rm O}\limits^ + $CHR′CH₂?HR″ and their molecular ion counterparts R$ \mathop {\rm O}\limits^{{\rm + } \cdot } $CHR′CH₂CH₂R″ have been studied by isotopic labelling and collision-induced dissociation, applying a potential to the collision cell in order to separate activated from spontaneous decompositions. The stability of CH₃$ \mathop {\rm O}\limits^ + $HCH(CH₃)CH₂?HCH₃, C₂H₅$ \mathop {\rm O}\limits^ + $HCH(CH₃)CH₂?HCH₃, CH₃$ \mathop {\rm O}\limits^ + $HCH(CH₃)CH₂?H₂, CH₃$ \mathop {\rm O}\limits^ + $HCH₂CH₂?HCH₃ and C₂H₅$ \mathop {\rm O}\limits^ + $HCH₂CH₂?HCH₃, has been demonstrated and their characteristic decomposition, alcohol loss, identified. For all these γ-distonic ions, the 1,4-H abstraction leading to their molecular ion counterpart exhibits a primary isotope effect.