Molten salt synthesis of potassium and barium niobates

The interaction of powdered niobium oxide with molten potassium and barium nitrate salts containing KOH was studied. It was shown that KNbO₃ can be obtained with the use of binary mixtures of the KOH-KNO₃ system. The BaNb₂O₆ compound can be synthesized in melts of the KNO₃-Ba(NO₃)₂ system. The treatment of Nb₂O₅ with melts of the system KNO₃-Ba(NO₃)₂-KOH with various KOH percentages allowed us to obtain mixtures of Ba₅Nb₄O_15.33 with Nb₁₂O₂₉ or Ba₅Nb₄O_15.48 with K_0.8Ba_0.2NbO₃.     

Der Transport von VO2 mit Cl2 und HCl + Cl2 und der Einfluß des O2-Bodenkörpergleichgewichtsdruckes auf den Transport

The Chemical Transport of VO₂ with Cl₂ and HCl + Cl₂ and the Influence of the O₂-Coexistence Equilibrium Pressure on the Transport Behaviour The transport behaviour of VO₂ with Cl₂, HCl, and Cl₂ was calculated and compared with the experimental results. VO₂ with the upper phase boundary transports with HCl and HCl + Cl₂ from the colder to the hotter zone, VO₂ of the lower phase boundary does not transport with HCl. The composition of the deposited VO₂ is near the upper boundary oxygen richer than in the start space. VO₂ does not transport with Cl₂.     

Bildung siliciumorganischer Verbindungen. 73. Reaktionen C-chlorierter 1,3-Disilapropane mit CH3MgCl

Formation of Organosilicon Compounds. 73. Reactions of C-chlorinated 1,3-Disilapropanes with CH₃MgCl (Cl₃Si)₂CCl₂ reacts with an excess of meMgCl (me = CH₃) in Et₂O (diethylether) forming (me₃Si)₂₂C?CH₂ mainly besides Si-methylated 1,3-disilapropanes with CmeCl, CHCl, CH₂ groups [6]. For investigating the mechanism of formation of the methylidengroup reactions were carried out with differently Si-methylated and Si-chlorinated 2-methyl-1-2-chloro-1,3-disilapropanes and 2,2-dichloro-1,3-disilapropanes. Whereas (me₃Si)₂CmeCl reacts neither with meMgCl nor with Lime. it forms (me₃Si)₂C?CH₂ and (me₃Si)₂CmeH with Li or Mg resp. The reaction starts with the metallation to (me₃Si)₂CmeLi and (me₃Si)₂Cme(MgCl) resp., followed by elimination of LiH and HMgCl resp. with formation of (me₃Si)₂C?CH₂. LiH and HMgCl resp. reduces (me₃Si)₂CmeCl to (me₃Si)₂CmeH. This mechanism is supported by the reactions of (me₃Si)₂CCl(CD₃). The Si-chlorination increases the reactivity of the CmeCl group and the created C?CH₂ group favours Si-methylation. The CCl₂ group is more reactive than the CmeCl group; (me₃Si)₂CCl₂ already forms the methyliden group with meMgCl in Et₂O via the not isolated intermediate (me₃Si)₂CCl(MgCl). which prefers the methylation to (me₃Si)₂Cme(MgCl). The n.m.r. data of the investigated compounds are given.     

π-Olefin-iridium-komplexe : IV. Umsetzungen von chloro-dien-iridium-verbindungen mit lithiumorganylen

The complexes [(1,3-C₆H₈)₂IrR] and [(1,3-C₇H₁₀)₂IrR] (R = CH₃, C₆H₅) are obtained by reaction of the corresponding chloro compounds with RLi. Interaction of [Ir(COD)Cl]₂ (COD = 1,5-cyclooctadiene) with CH₃Li in the presence of 1,3-cyclohexadiene or isoprene yields [(COD)(1,3-C₆H₈IrCH₃] and [(COD)(C₅H₈IrCH₃], respectively. The products of the reaction of chlorodicyclodieneiridium with n-C₄H₉Li depend on the ring size of the cyclodiene ligands; with 1,3-cyclohexadiene [(1,3-C₆H₈)₂IrH] is formed while with 1,3-cycloheptadiene [(1,3-C₇H₁₀)(C₇H₉)Ir] is obtained together with [(1,3-C₇H₁₀)₃Ir₂(μ-H)₂]. Chemical and spectroscopic properties of the new compounds are discussed.     

Derivatives of M(η5-C5H5)2 (M = Mo,W) with alkenylpyridines and related ligands

Reactions of ligands 2-vinylpyridine 1, 4-vinylpyridine 2, 2-allylpyridine 3, 1-allylpyrazole 4, acrylonitrile 5 and allylcyanide 6 with the metallocene derivatives [Mo(η⁵-C₅H₅)₂H₃][PF₆] 7, [Mo(η⁵-C₅H₅)₂HI] 8, [W(η⁵-C₅H₅)₂H₃] [PF₆] 9, [Mo(η⁵-C₅H₅)₂H₂] 10, [M(η⁵-C₅H₅)₂Br₂], M = Mo 11, M = W 12 are described. Reaction of 7 with 1, 8 with 1, 3 with 8 and 4 with 8 gave mixtures of metallocyle isomers resulting from coordination of the nitrogen atom to molybdenum followed by internal hydrometallation; reaction of 11 with 1 gave an olefinic π complex; reaction of either 9 or 11 with 1 gave intractable oils; reactions of 8 with 2, 11 with 5, 12 with 5, 11 with 6 and 12 with 6 yielded monosubstituted products in which the ligand is N-coordinated.     

Ti7Cl16 und Ti7Br16 sowie weitere Untersuchungen mit Titanhalogeniden. Al2X6 als Komplexbildner

Ti₇Cl₁₆ and Ti₇Br₁₆ and Further Investigations with Titanium Halides. Al₂X₆ as a Complex Forming Agent TiCl_3,s can be transported with Al₂Cl₆ via TiAlCl_6,g in a temperature gradient. The equilibrium of this reaction was studied by mass spectroscopy. There is no indication of the existence of a TiAl₂Cl₉ molecule as assumed in the literature. β-TiBr₃ was prepared from the elements in the presence of the transporting agent Al₂Br_6,g. The transport of TiCl₂ with Al₂Cl_6,g involves, as an important step, the disproportionation which is favoured by the reaction of Ti with the glass wall. If the disproportionation is made impossible by addition of Ti the novel compound Ti₇Cl₁₆ is obtained. Independent of Ti₇Cl₁₆, a phase TiCl_{(2 + x)} with a broad range of homogeneity exists. The compound Ti₇Br₁₆, being isostructural with Ti₇Cl₁₆, was also prepared. Results of magnetic measurements and observations on the thermal decomposition of the compounds are reported.     

Antimon-organo-Verbindungen. V. Zum Reaktionsverhalten des Phenylstibins

Organoantimony Compounds. V. The Reactivity of Phenyl Stibine C₆H₅SbH₂, synthesized by the reduction of C₆H₅SbCl₂ with LiBH₄, reacts with LiR under certain conditions forming (C₆H₅Sb)_n and H₂ or give by a partially elimination of H₂ stibides with a different structure. The latter react with alkyl and aryl halides forming tert. stibines which may be characterized as the corresponding dibromides. The preparation of C₆H₅SbNa₂ and its reaction with C₂H₅Br, Cl(CH₂)₄Cl and C₆H₅(Cl)C?N? N?C(Cl)C₆H₅ are described.     

The reactivities of TiO2 (rutile and anatase) for the solid-state reactions with BaSO4 and BaCO3

DTA and isothermal kinetic studies were carried out on the reactions of BaSO₄ or BaCO₃ with TiO₂ (anatase and rutile) to BaTiO₃. In the initial steps, the reactions of BaSO₄ with TiO₂ (anatase) proceeded to BaTi₄O₉, of BaSO₄ with TiO₂ (rutile) to BaTi₃O₇, and of BaCO₃ with TiO₂ (anatase and rutile) to Ba₂TiO₄, respectively. These reactions were connected with the formation of binary metal oxide through some intermediates, which are BaSO₄ or BaCO₃ incorporated with TiO₂. The reactivity of anatase was higher than that of rutile in all reaction systems.     

The reactions of Ir(CO)Cl(PPh3)2 with HSnPh3

A reinvestigation of the reaction of Ir(CO)Cl(PPh₃)₂, 1 with HSnPh₃ has revealed that the oxidative-addition product Ir(CO)Cl(PPh₃)₂(H)(SnPh₃), 2 has the H and SnPh₃ ligands in cis-related coordination sites. Compound 2 reacts with a second equivalent of HSnPh₃ by a Cl for H ligand exchange to yield the new compound H₂Ir(CO)(SnPh₃)(PPh₃)₂, 3. Compound 3 contains two cis- related hydride ligands. Under an atmosphere of CO, 1 reacts with HSnPh₃ to replace the Cl ligand with SnPh₃ and one of the PPh₃ ligands with a CO ligand and also adds a second equivalent of CO to yield the 5-coordinate complex Ir(CO)₃(SnPh₃)(PPh₃), 4. Compound 4 reacts with HSnPh₃ by loss of CO and oxidative addition of the Sn-H bond to yield the 6-coordinate complex HIr(CO)₂(SnPh₃)₂(PPh₃), 5 that contains two trans-positioned SnPh₃ ligands.     

Zur Reaktion von Phosphor(Arsen)-chalkogeniden mit Phosphor(Arsen)-triiodid

Reactions of Phosphorus(Arsenic)chalcogenides with Phosphorus(Arsenic)triiodide The specific heats and enthalpies of melting of the tetraphosphorustrithio(seleno)-diiodides have been determined. For the preparation of β-P₄S₃I₂ a new mthod by reacting P₄S₃ with PI₃ in CS₂ solution was found. Experiments to prepare compounds of the type As₄S₃I₂ by the classical methods for the preparation of the resp. phosphorus compounds failed. The reaction of As₄S₃ with AsI₃ leads to the formation of As₄S₄. The other sulphides of the As? S system As₂S₃ and As₄S₄ react with AsI₃ to AsSI, however, in the reaction of As₄S₄ the addition of S is necessary.     

Perfluoralkyljod-verbindungen: das trifluormethyljoddinitrat CF3J(NO3)2

CF₃I(NO₃)₂ is formed from the reactions of CF₃IF₂ or CF₃IO with N₂O₅ as well as CF₃I with ClNO₃. During the reactions of CF₃IF₂ with N₂O₅ or CF₃I with ClNO₃ the intermediate products CF₃IF(NO₃) or CF₃ICl(NO₃) can be identified. The preparations, properties, ¹⁹F-nmr spectra and the thermal decomposition of CF₃I(NO₃)₂ are described.     

Die Reaktionen von Benzoylierungsmitteln mit Phosphoriger Säure

Reactions of Benzoylating Agents with Phosphorous Acid H₃PO₃ reacts with (C₆H₅CO)₂O to yield C₆H₅C(OH)(PO₃H₂)₂ 1 . In contrast, the reaction with C₆H₅COCl proceeds with the formation of C₆H₅CCl(PO₃H₂)₂ 2 and p-ClC₆H₄CH(PO₃H₂)₂ 3 . The best yields of 2 and 3 are obtained, if the reaction are carried out under pressure. 2 is rapidly hydrolysed in alkaline solution at elevated temperatures to 1 .     

The synthesis of some (pentafluorophenyl)germanium compounds

Tris(pentafluorophenyl)germanium bromide reacts with lithium aluminium hydride or triethylgermane to give tris(pentafluorophenyl)germane. On reaction with HgR₂ [where R = Et, Et₃Ge and (Me₃Si)₂N] or reaction with diethylcadmium, the latter gave the hitherto unknown [(C₆F₅)₃Ge]₂Hg or [(C₆F₅)₃Ge]₂Cd. The germylmercurial compound could also be prepared by reaction of metallic mercury with [(C₆F₅)₃Ge]₂Cd and by exchange of bis(triethylgermyl)mercury with (C₆F₅)₃GeBr. Some reactions of bis[tris(pentafluorophenyl)germyl]mercury are discussed.     

Low oxidation state ruthenium chemistry : IV. The reactions of M(CO)2(PPh3)3 complexes (M = Fe,Ru) and the hydrogenation and isomerization of alkenes catalyzed by RuL(CO)2(PPh3)2 (L = H2, PPh3)

The complexes M(CO)₂(PPh₃)₃ (I, M = Fe; II, M = Ru) readily react with H₂ at room temperature and atmospheric pressure to give cis-M(H)₂(CO)₂(PPh₃)₂ (III, M = Fe;IV,M = Ru). I reacts with O₂ to give an unstable compound in solution, in a type of reaction known to occur with II which leads to cis-Ru(O₂)(CO)₂(PPh₃)₂(V). Even compound IV reacts with O₂ to give V with displacement of H₂; this reaction has been shown to be reversible and this is the first case where the displacement of H₂ by O₂ and that of O₂ by H₂ at a metal center has been observed. III and IV are reduced to M(CO)₃(PPh₃)₂ by CO with displacement of H₂; Ru(CO)₃- (PPh₃)₂ is also formed by treatment of IV with CO₂, but under higher pressure. Compounds II and IV react with CH₂CHCN to give Ru(CH₂CHCN)(CO)₂- (PPh₃)₂(VI) which reacts with H₂ to reform the hydride IV.cis-Ru(H)₂(CO)₂(PPh₃)₂(IV) has been studied as catalyst in the hydrogenation and isomerization of a series of monoenes and dienes. The catalysts are poisoned by the presence of free triphenylphosphine. On the other hand the ready exchange of H₂ and O₂ on the “Ru(CO)₂(PPh₃)₂” moiety makes IV a catalyst not irreversibly poisoned by the presence of air. It has been found that even Ru(CO)₂(PPh₃)₃(II) acts as a catalyst for the isomerization of hex-1-ene at room temperature under an inert atmosphere.     

Metallothermische Reduktion des Tribromids und -iodids von Dysprosium mit Alkalimetallen

Metallothermic Reduction of the Tribromide and -iodide of Dysprosium with Alkali Metals Metallothermic reduction (900–1000°C, 2–3 d, tantalum capsules) of DyX₃ (X = Br, I) with alkali metals (A = Li? Cs) results in the case of lithium and sodium (except for the system DyBr₃/Li) in the formation of the dihalides DyX₂ (DyI₂ with the CdCl₂-type, DyBr₂ with the SrI₂-type of structure). The reduction of DyI₃ with potassium leads to K_1.71DyI₄ which crystallizes hexagonally with a = 1 446.7(2) pm and c = 473.3(1) pm, space group P6 2m (Z = 3). In K_1.71DyI₄, [DyI₆]-octahedra are edge-connected forming chains along [001] that are linked via K⁺. With A = K, Rb, Cs, variants of the perovskite-type of structure with the composition ADyX₃ are obtained. They crystallize with the tetragonal NaNbO₃-II-type (CsDyBr₃) or with the orthorhombic GdFeO₃-type of structure (KDyBr₃, RbDyX₃, CsDyI₃).     

Amidometallate von Lanthan und Gadolinium und Umsetzung von Lanthan,Gadolinium und Scandium mit Ammoniak

Amidometallates of Lanthanum and Gadolinium and the Conversion of Lanthanum, Gadolinium, and Scandium with Ammonia By reaction of the metals with NsNH₂ and NH₃ in the hightemperature- autoclave Na₃[La(NH₂)₆], Na₃[Gd(NH₂)₆], and Na[Gd(NH₂)₄] were prepared, but not any compound of Sc. By corresponding experiments with NH₄I only La(NH₂)₃, GdN, and ScH₂ were obtained. Na₃[La(NH₂)₆] and Na₃[Gd(NH₂)₆] are isotypic with Na₃[Y(KH₂)₆], Na[Gd(NH₂)₄] with Na[Yb((NH₂)₄]. The thermal behaviour of the prepared amides was characterized by DTA and tensimetry.     

Ni2Sn2Zn from single‐crystal X‐ray diffraction

Dinickel ditin zinc, Ni₂Sn₂Zn, crystallizes in the cubic space group , with a lattice parameter of a = 8.845 (1) Å and with all atoms occupying special positions. The crystal structure exhibits pronounced similarities with that of the quaternary compound Ni_5.20Sn_8.7Zn_4.16Cu_1.04. It shares structural features with other compounds in the Ni–Sn–Zn system, such as Ni₅Sn₄Zn and Ni₃Sn₂.     

Ethylene/propylene copolymers with vanadium-based catalysts: Cocatalyst effect

Ethylene/propylene copolymers were obtained with vanadium-based catalysts. Different aluminium alkyls were employed as cocatalyst: Al(C₂H₅)₂Cl/promoter, Al(i-C₄H₉)₃, Al(n-C₆H₁₃)₃. and Al(n-C₈H₁₇)₃. The influence of the cocatalyst on the molecular weight, the molecular weight distribution and the microstructure of the copolymers was investigated through GPC, DSC, ¹³C–NMR analysis and fractionation. AIR₃ afforded a polymerization activity that was much higher with respect to Al(C₂H₅)₂Cl/nBPCC, but with the latter cocatalyst system copolymers were obtained with a more homogeneous distribution of the monomers and the absence of crystallinity. A comparison with ethylene/propylene copolymers obtained with a V(Acac)₃/Al(C₂H₅)₂Cl/promoter and with a high-yield Ti-based catalyst is also presented.     

Ein Synergetischer Effekt bei Chlorierungen von Silicagel bzw. Metakaolin mit gasförmigen,Aluminiumchlorid enthaltenden Chlorierungsmitteln

A Synergetic Effect in Chlorination of Silicagel and Metakaolin with Aluminium Chloride Containing Chlorinating Agents The reactivity of silicagel with CCl₄, C₂Cl₆, C₂Cl₄, COCl₂, S₂Cl₂/Cl₂, and Cl₂/carbon is low up to 1000 K. Aluminium chloride under these conditions is a little more reactive above 600 K. But gaseous mixtures of aluminium chloride with CCl₄, C₂Cl₆, and S₂Cl₂/Cl₂ resp., show a synergetic effect: They attain conversion grades much higher than the sum of those obtained with each of the single components. The reactivity of aluminium chloride/CCl₄ mixtures with silicagel in dependence on temperature and partial pressure has been followed. Metakaolin is reacted by such a mixture synergetically and with increased silicate conversion. Practical consequences of this effect are demonstrated and essential phenomena involved in metakaolin chlorination are explained. A mechanistic model of the synergetic effect has been developed.     

NaEu2Cl6 und Na0,75Eu2Cl6: Gemischtvalente Chloride des Europiums mit Natrium

NaEu₂Cl₆ and Na_0.75Eu₂Cl₆: Mixed Valent Chlorides of Europium with Sodium The reaction of Na₂EuCl₅ with Eu metal in sealed gold tubes yields blue single crystals of NaEu₂Cl₆. It crystallizes with the hexagonal crystal system (space group P6₃/m) with a = 755.74(8) pm, c = 429.81(5) pm, Z = 1; the structure is closely related to the UCl₃-type. Green single crystals of Na_0.75Eu₂Cl₆ were first obtained as a by-product in the synthesis of Na₂EuCl₅ in evacuated silica tubes and may be prepared by reduction of EuCl₃ with sodium. Na_0.75Eu₂Cl₆ crystallizes isotypic to NaEu₂Cl₆ with a = 753.69(11) pm and c = 416.3(2) pm.