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  • Chemistry  (25)
  • transition metal acetates  (1)
  • 1
    ISSN: 1572-8943
    Keywords: catalytic activities and selectivities ; thermal decomposition ; transition metal acetates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermal decomposition of acetates of the transition metals Fe, Co, Ni, Mn and Cu in molecular hydrogen has been investigated by means of combined thermogravimetry/mass spectrometry, X-ray diffraction, and transmission as well as scanning electron microscopy. In the context of the reproducible preparation of the parent phases, i.e. the hydrated or anhydrous metal(II) acetates, single crystalline Fe3(CH3COO)6(DMSO)2, a novel DMSO solvate of iron(II) acetate, has been isolated and its crystal structure has been determined by means of X-ray diffraction. For the series of metal(II) acetates it has been found that the course of the thermal degradation in molecular hydrogen, in particular the formation of the gaseous products, strongly depends on the transition metal ion present in the parent compound. The detailed characterisation of the solid products revealed, that phases exhibiting different catalytic activities and selectivities are formed as micro- or nanocrystalline metals and/or metal oxides.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 421 (1976), S. 61-70 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of a Hydroxostannate: Copperdiammine-hexahydroxostannate Cu(NH3)2Sn (OH)6Single crystals of Cu(NH3)2, Sn(OH)6, have been prepared by the reaction of K2Sn(OH)6, with Cu(NO3)2· 3 H2O in aqueous solution of NH3. The complex crystallizes in the triclinic space group P1 with a = 5.643(2) Å, b = 6.621(2) Å, c = 4.885(2) Å, α = 91.83(3)°, β = 93.58(3)°, γ = 107.69(3)° and Z = 1. The crystal structure has been solved by Pattersonsyntheses. The hydrogen atoms could be localized by difference Fourier syntheses. The structure contains infinite chains of alternating Sn(OH)6- and Cu(OH)4(NH3)2-octahedra linked parallel to the b-axis by common edges. The chains are connected by hydrogen-bonding to their neighbouring chains. An almost regular octahedra is found for the coordination of the Sn-atoms, whereas the Cu(OH)4(NH3)2-octahedra show a pronounced (4+2)-distortion with two OH—-groups in the axial positions in a distance of 2.627(2) Å. The structure can also be described in terms of slightly distorted hexagonal close packed layers of oxygen and nitrogen. The metal atoms occupy 1/4 of the octahedral sites in an ordered arrangement. Thus the structure bears a close relationship to thc layer structure of α-NbI4.
    Notes: Einkristalle von Cu(NH3)2Sn(OH)3 wurden durch Umsetzung von K2Sn(OH)6 mit Cu(NO3)2 · 3 H2O in wäßriger ammoniakalischer Lösung gewonnen. Die Verbindung kristallisiert in der triklinen Raumgruppe P1 mit a = 5,643(2) Å, b = 6,621(2) Å, c = 4,885(2) Å, α = 91,83(3)°, β = 93,58(3)°, γ = 107,69(3)° und Z = 1. Die Kristallstruktur wurde aus Pattersonsynthesen aufgeklärt, und aus Differenzfouriersynthesen konnten auch die Positionen der Wasserstoffatome ermittelt werden. Die Struktur enthält unendliche Ketten von alternierenden Sn(OH)6-und Cu(OH)4(NH3)2-Oktaedern, welche parallel zur b-Achse über gemeinsame Kanten verknüpft sind. Die Ketten sind durch Wasserstoffbrückenbindungen mit ihren Nachbarketten verknüpft. Während das Sn(OH)6-Oktaeder nahezu regulär gebaut ist, zeigt das Cu(OH)4(NH3)2-Oktaeder eine ausgeprägte (4+2)-Verzerrung mit zwei OH--Gruppen in den axialen Positionen in einem Abstand von 2,627(2) Å. Die Struktur kann auch als Folge von leicht verzerrten hexagonal dichtest gepackten Schichten von Sauerstoff und Stickstoff beschrieben werden, wobei die Metallatome 1/4 der Oktaederlücken geordnet besetzen. Sie zeigt eine enge Verwandtschaft mit der Schichtstruktur des α-NbJ4.
    Additional Material: 5 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 407 (1974), S. 244-256 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: X-ray and Spectroscopic Studies on the two Modifications of Dichloro-2,2′-bipyridyl Platinum(II)Two modifications of PtCl2(2,2′-bipyridyl) are investigated by X-ray diffraction and spectroscopic methods. The difference between both forms consists only in the packing of the planar complex units within the crystal. For the red coloured modification a columnar structure is derived from X-ray single crystal data, in which the nearest distance between planar complex units stacked above each other is 3.40 Å. The yellow form, however, does not form a columnar structure. It is built up from essentially isolated complex molecules without any feasible Pt-Pt-interaction (shortest Pt-Pt-distance: ca. 4.5 Å). Infrared and electronic spectra confirm the proposed structures. In the visible range only electronic transitions of the type 5d(Pt) → π*(bipyridyl) are observed which are also responsible for the different colours of the two modifications.
    Notes: Röntgenographische und spektroskopische Untersuchungen an zwei Modifikationen von PtCl2(2,2′-dipyridyl) zeigen, daß der Unterschied zwischen den beiden Formen lediglich in einer verschiedenen Packung der planaren Komplexeinheiten im Kristall besteht. Aus Einkristall-Röntgendaten wird für die rote Modifikation eine Kolumnarstruktur postuliert, in der die Komplexebenen im Abstand von 3,40 Å übereinander geschichtet sind. Die gelbe Form besitzt dagegen keine Kolumnarstruktur. Sie muß aus weitgehend isolierten Komplexbausteinen ohne merkliche Pt-Pt-Wechselwirkung (kürzester Pt-Pt-Abstand:etwa 4,5 Å) aufgebaut sein. Infrarot- und Elektronenspektren beider Formen bestätigen die Strukturvorschläge. Im sichtbaren Bereich lassen sich nur inverse Elektronentransfer-übergänge vom Typ 5d(Pt)→ π*(Dipyridyl) beobachten, die auch für die unterschiedliche Farbe der beiden Substanzen verantwortlich sind.
    Additional Material: 5 Ill.
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  • 4
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Influence of the structure on the corrosion behaviour of aluminium bronzes in sodium chloride solutionThe influecne of various structural components and their distribution on the corrosion behaviour of binary and complex aluminium bronzes (cast INOXYDA alloys) in a 3% solution of sodium chloride has been investigated qualitatively and quantitatively. Corrosion tests were carried out over a period of 850 h and are interpreted on the basis of single phase properties.The corrosion resistacne of binary and INOXYDA 3 type alloys is markedly decreased if even small amounts of y2 phase are precipitated in a continuous manner. The occurance of this constituent causes an intense and dangereous dealuminisation reaction. The eutectoid mixture (α + y2) is always less corrosion resistant than corresponding martensitic structures.While the corrosion behaviour of these alloys is strongly influenced by heat treatment a far less pronounced effect is observed with alloys containing Fe and Ni (type INOXYDA 53 or 90). This is directly related to the fact that precipitation of y2 is prevented by the addition of Fe and especially of Ni. Such alloys are mainly composed of Ni. Such alloys are mainly composed of α and passive Fe- and Ni-rich K phase. If retained martensite or y2 are present in addition to the mentioned phases (e.g. in the as cast condition) corrosion resistance is decreased. Appropriate heat treatment results in plain (α + K) structures while simultaneously segregations at α/K grain boundaries disappear and corrosion resistance is improved.
    Notes: Der Einfluß verschiedener Gefügeausbildungen auf die Korrosionseigenschaften binärer und komplexer Aluminiumbronzen (INOXYDA-Gußlegierungen) in ruhender 3%iger Kochsalzlösung wurde ermittelt. Die qualitativen und quantitativen Resultate aus Standversuchen über 850 h wurden anhand des korrosions chemischen Verhaltens der einzelnen Gefügebestandteile diskutiert.Bei binären Legierungen und INOXYDA 3 führen schon geringe Mengen zusammenhängend ausgeschiedener y2-Phase zu einer deutlichen Abnahme der Korrosionsbeständigkeit, wobei intensive Entaluminierung auftritt. Die Gleichgewichtsgefüge mit den Phasen α und y2 sind in jedem Fall weniger beständig als die Abschreckgefüge mit martensitischen Anteilen.Im Gegensatz zu diesen Legierungen konnte bei Fe- und Ni-haltigen Bronzen vom Typ INOXYDA 53 oder 90 nur ein viel geringerer Einfluß der Wärmebehandlung auf das Korrosionsverhalten beobachtet werden. Dies steht eindeutig mit der Unterdrückung von y2 durch Fe- und besonders Ni-Zusätze in Zusammenhang. Solche Legierungen bestechen praktisch nur aus α und der passiven, Fe- und Ni-reichen K-Phase. Enthalten die Mehrstoffbronzen jedoch zusätzlich Restmartensit oder y2, wie das im Gußzustand normalerweise der Fall ist, so ist die Korrosionsbeständigkeit herabgesetzt. Durch geeignete Wärmebehandlung kann auch hier ein reines (α + K)-Gefüge erreicht werden wobei gleichzeitig Seigerungen innerhalb α und K abgebaut und der Korrosionswiderstand erhöht wird.
    Additional Material: 12 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 74 (1962), S. 294-294 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 81 (1969), S. 470-470 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 43 (1960), S. 77-80 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Wasserfreies ZnBr2 und ZnJ2 wurde morphologisch und röntgenographisch untersucht.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 43 (1960), S. 1947-1950 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: γ-MnO2 can be partly reduced with N2H2 without changing its lattice. The volume of the elementary cell increases approximatly linearly with decreasing MnIV content. It is assumed that the reduction occurs in a one phase topochemical reaction, electrons and protons migrating through the lattice according to the formula \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm MnO}_2 + {\rm n} \cdot {\rm e}^ - + {\rm n} \cdot {\rm H}^ + = {\rm MnO}_{2 - {\rm n}} ({\rm OH)}_{{\rm n} \cdot } $$\end{document}.
    Additional Material: 2 Tab.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 44 (1961), S. 1049-1054 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of anhydrous chromium dichloride (CrCl2) has been determined by the X-ray powder method. CrCl2 has an orthorhombic elementary cell with a = 6,624 ± O.006 Å b = 5,974 ± 0,006 Å, c = 3,488 ± 0,004 Å, space group D2h12-Pnnm. The values for the only free parameters xcl and ycl have been refined by a least squares treatment. The structure of CrCl2 is related to the PdCl2 structure and, as expected from the crystal field theory, to the structure of CuCl2. Each Cr atom is surrounded nearly quadratically by four Cl atoms at a distance of 2,375 Å and two Cl atoms at 2,91 Å, completing a deformed octahedron.
    Additional Material: 2 Tab.
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  • 10
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: o,o′-Dihydroxyazo compounds are spectral sensitizers for the photosemiconductor properties of zinc oxide. It is shown that 1-(2-hydroxyphenylazo-)-2-naphthol (II) forms a 1:1 Zn complex on the surface of ZnO particles if adsorbed from toluene solution. With most samples of ZnO a Langmuir type adsorption isotherm is obtained. The concentration of the dye at saturation relative to the BET surface of the ZnO particles correponds to a slightly oblique edge-on arrangement of the dye molecules on the surfaces.In the case of ZnO pretreated with propionic acid and having taken up dye in excess of a monolayer, it can be shown by electron microscopy that tail-like complexes (zinc: dye ratio = 1:1) are formed, and that these complexes contain zinc which was originally on the particle surfaces.
    Additional Material: 8 Ill.
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