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  • 550 - Earth sciences  (6)
  • Inorganic Chemistry  (5)
  • J26
  • 2005-2009  (6)
  • 1980-1984  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Photoelektronenspektroskopie an NiobiodidenProfessor Walter Rüdorff zum 75. Geburtstage am 3. Oktober 1984 gewidmet (1984)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 516 (1984), S. 55-66 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoelectron Spectroscopy on Niobium IodidesThe photoelectron spectra (AlKα, HeI) of NbI5, NbI4, Nb3I8, Nb6I11, HNb6I11, Nb6I8(CH3NH2)6, Nb6I8(C3H7NH2)6, and Nb are measured and discussed. It is shown that the binding energy of the niobium core levels depends linearly on the oxidation number n (n = I/Nb). The relation BE = 201.8 + 1.07 · n holds for the Nb 3d5/2 level. Using this relation the hydridic character of the hydrogen in HNb6I11 becomes plausible and the increased electron concentration of the Nb6I8 cluster in the compounds Nb6I8(CH3NH2)6 and Nb6I8(C3H7NH2)6 is verified. Energy gaps Eg = 0.40 (0.45) eV are found for Nb6I11(HNb6I11) and for the amines the top of the valence band is 0.70 (CH3NH2) and 0.68 eV (C3H7NH2), resp. below the Fermi level.
    Notes: Es werden die Photoelektronenspektren (AlKα, HeI) von NbI5, NbI4, Nb3I8, Nb6I11, HNb6I11, Nb6I8(CH3NH2)6, Nb6I8(C3H7NH2)6 und Nb gemessen und diskutiert. Es läßt sich zeigen, daß die Bindungsenergie BE der Niob-Rumpfniveaus linear von der Oxydationszahl n (n = I/Nb) abhängt; für das Nb 3d5/2-Niveau ergibt sich die Beziehung BE = 201,8 + 1,07 · n. Durch Anwendung dieser Beziehung wird der hydridartige Charakter des Wasserstoffs in HNb6I11 wahrscheinlich gemacht sowie die Zunahme der Elektronenkonzentration im Nb6I8-Cluster der Verbindungen Nb6I8(CH3NH2)6 und Nb6I8(C3H7NH2)6 belegt. Für Nb6I11(HNb6I11) ergibt sich eine verbotene Zone Eg = 0,40 (0,45) eV, für die Amine ist der Abstand der Oberkante des Valenzbandes zur Fermi-Kante 0,70 (CH3NH2) bzw. 0,68 eV (C3H7NH2).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19845160909
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  • 2
    Electronic Resource
    Electronic Resource
    Preparation, Properties, and ESCA Characterization of Vanadium Surface Compounds on Silicagel. I (1981)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 483 (1981), S. 181-192 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung, Eigenschaften und ESCA-Charakterisierung von Vanadium-Oberflächenverbindungen an Silicagel. IV 2p3/2-Bindungsenergiewerte (BE) von 18 Vanadium-Verbindungen in Sauerstoff- und Chlorumgebung wurden ermittelt. Bindungsenergien in Abhängigkeit von der Oxidationszahl wurden hinsichtlich eines linearen Zusammenhangs kritisch überprüft, um so geeignete Modellverbindungen für Vergleichstandards auswählen zu können.Im allgemeinen beobachtet man bei einer Zunahme der formalen Oxydationszahl auch eine Erhöhung der Bindungsenergiewerte; im Einzelfall kann dies aber durch elektronenschiebende/ziehende Liganden überdeckt werden.Die mit Hilfe eines Computerprogramms durchgeführte Subtraktion des überlagernden O 1s Satellitenpeaks verbesserte die Genauigkeit der Vanadium 2p3/2-Bindungsenergiewerte erheblich in Oberflächenverbindungen.Die gefundenen Bindungsenergiewerte für (≡Si—O)3V=O(I), (≡Si—O)3V(II) und (≡Si—O)3V—(O2) (III) zeigen im Vergleich zu den trägerfreien Standardverbindungen eine BE-Erhöhung um 2,1 eV und damit die ausgeprägte elektronenziehende Wirkung des Trägermaterials auf das Vanadium in Oberflächenverbindungen. Über ESCA-Daten eines Oberflächen-Peroxokomplexes (III) wird zum ersten Male berichtet; einige Folgerungen der Ergebnisse werden diskutiert.
    Notes: Binding energies (BE) of 18 pure vanadium compounds (V 2p3/2 niveau) were measured in selected oxygen and chlorine environments, linearity of BE vs. oxidation states scrutinized and appropriate model compounds chosen as comparative standards.The general trend is an increase of BE with formal oxidation state; in particular, it could be counterbalanced by electron donating/withdrawing ligands on the V atom.A graphical (computerized) background substraction method was utilized to remove an interfering O 1s satellite peak and to enhance accuracy of BE values in surface compounds.BEs of (≡Si—O)3V=O (I), (≡Si—O)3V (II), and (≡Si—O)3V—(O2) (III) were determined. By comparison to standards positive BE shifts of about 2.1 eV were derived indicating the strong electron withdrawing (“electron sink”) effect of the support on V in surface compounds. This is the first reported ESCA data on a surface peroxo complex, (III). Some implications of the results are also discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19814831223
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation, Properties, and ESCA Characterization of Vanadium Surface Compounds on Silicagel. II (1981)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 483 (1981), S. 193-204 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung, Eigenschaften und ESCA-Charakterisierung von Vanadium-Oberflächenverbindungen an Silicagel. IIBindungsenergiewerte (BE) und Intensitätsverhältnisse in Vn/SiO2 (n = 3, 4 und 5) in Abhängigkeit von der Vanadium-Konzentration und Liganden L wurden untersucht. Die Ermittlung optimierter Produkte und ESCA-Proben wird beschrieben. Anhand dieser Ergebnisse werden die Bedingungen demonstriert, unter denen ESCA zuverlässige Informationen über feinverteilte Oberflächen-Verbindungen liefern kann.Der geeignete Konzentrationsbereich für wäßrige Dotierungen liegt zwischen 0,4 bis 1,2% VIII und 1,0 bis 1,2% für VV; in nichtwäßrigen (metallorganischen) Präparaten ergeben sogar 0,15 bis 0,4% VIII und 0,4% VV brauchbare Spektren. Die ESCA-Daten des Peroxo-Komplexes (≡Si—O)3V—(O2) (I) Bestätigen diese Trends.Außerordentlich feinverteilte Oberflächen-Verbindungen erhält man aus Dotierungen mit V[N(SiMe3)2]3. Hier ist eine Konzentration von 0,4 bis 0,5% VIII (oder VV) optimal und die obere Grenze.Beweise für die Formulierung von VnSiO2 als dreibeinige Oberflächen-Verbindungen sind zusammengefaßt; die Bedeutung des Additivitätsprinzips für die Erklärung und Voraussage elektronischer Verhältnisse bei Oberflächen-Verbindungen wird erläutert.Innerhalb der Serie (≡SiO)3V—L (mit L = ohne Liganden, =0, und —Oz) wurden die chemischen Verschiebungen für ≡Si—O—V (0,7 eV); V=O (0,6 eV) und V—(O2) (0,4 eV) ermittelt. Die BE-Beiträge einiger Donorliganden (und —Cl) werden abgeschätzt. In (I)deuten die ESCA-Daten eine formale Oxydationszahl nahe +4 an.Grenzen der ESCA-Methode werden erwähnt und Erweiterungen des Additivitätsprinzips diskutiert.
    Notes: Binding energy (BE) behavior and signal intensity as function of V conc. and ligands L were critically examined in Vn/SiO2 species (where n = +5, +4, and +3) and securing of optimized products and ESCA samples is described. The results moreover demonstrate conditions and approaches whereby ESCA can provide reliable information on highly diluted surface compound systems.From aquous media 1.0-1.2 wt. % VV and 0.4-1.2 wt. % VIII proved to be preferred ranges whereas in non aqueous (metalorganic) preparates the surprisingly low concentration of 0.4-0.15 wt. % VIII gave usable spectra and even 0.4 wt. % VV could be measured. ESCA data with the peroxo complex (≡Si—O)3V—(O2) (I) confirmed these trends.Superiorly subdivided surface compounds (reflected in the quality of spectra) are obtainable from V[N(SiMe3)2]3 impregnations where 0.4-0.5 wt. % VIII (or VV) are maximum/optimum conc. limits.Evidence for formulating Vn/SiO2 as three legged surface compounds is summarized and diagnostic/predictive uses of the additivity principle for surface electron states illustrated.In the (≡Si—O)3V—L series, where L = none, =O, and —(O2) positive ΔBE shifts for ≡Si—O—V (0.7 eV); V=O (0.6 eV); and V—(O2) (0.4 eV) were estimated. Tentative BE contributions of some donor ligands (and —Cl) are also suggested. In (I) ESCA indicated a formal oxidation state of approx. +4.Certain limits (precautions) with ESCA are noted and extensions of the additivity relationship discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19814831224
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  • 4
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XXX. Synthese und Charakterisierung von Nitrobenzylnickel-Verbindungen (1980)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 462 (1980), S. 177-184 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Transition Metal Alkyl Compounds. XXX. Synthesis and Characterization of Nitrobenzyl Nickel Compounds(C2H5)2Ni · dipy reacts with benzyl chlorides forming complexes of the type RNiCl · dipy. In this way nitro groups containing thermally stable organonickel compounds can be obtained, which cannot be achieved by means of organolithiiim or Grignard reagents. - In a similar way (C2H5)Ni · dipy reacts with to form · dipy.The composition of the compounds achieved was proved by analysis, by characteristic reactions, magnetic moments, and in part by their IR and M spectra.
    Notes: (C2H5)2Ni · dipy reagiert mit Benzylchloriden zu Benzylnickelchlorid-Komplexen des Typs RNiCl · dipy. Auf diesem Wege sind auch Nitrogruppen enthaltende thermisch stabile Organonickelverbindungen zugängig, die mittels Organolithium-oder Grignardverbindungen nicht erhalten werden können. - Auf analoge Weise reagiert (C2H5)2Ni · dipy mit zu · dipy.Die Zusammensetzung der erhaltenen Verbindungen wurde analytisch, durch die magnetischen Momente sowie IR-Daten und M-Spektren und durch charakteristische Reaktionen gesichert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19804620120
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation, Properties, and ESCA Characterization of Vanadium Surface Compounds on Silicagel. III (1981)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 483 (1981), S. 205-218 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung, Eigenschaften und ESCA-Charakterisierung von Vanadium-Oberflächenverbindungen an Silicagel. III.Die leicht darstellbaren Hexamethyldisilazen-Derivate der Übergangsmetalle (z. B. M—HMDS) werden als neuartiges Reagenz zur Darstellung von Oberflächen-Verbindungen des Typs ≡Si—O—M beschrieben. Folgeprodukte dieser Umsetzungen, ≡Si—O—SiMe3 und ≡Si—N(SiMe3)2, schaffen dabei eine hydrophobe Umgebung, die durch Temperaturerhöhung (300-400°C) beseitigt werden kann. Die Reaktionsfähigkeit der M—N-Bindungen mit Oberflächen-Silanolgruppen und gespannten Siloxaneinheiten kann durch eine Koordination von Liganden L (auch Lösungsmittelmoleküle) beeinflußt werden.Dreibeinige Vanadium(III)-Oberflächen-Verbindungen lassen sich direkt durch thermisches Aktivieren von V[N(SiMe3)2]3 auf SiO2 in neutraler oder reduzierender Atmosphäre erhalten. Der Reaktionsablauf wurde anhand von ESCA- und Reflexionsspektren verfolgt. Dotierungen aus benzolischer Lösung (0,40-0,45 % V) bei anschließendem Erhitzen auf 400-800°C ergaben optimierte Produkte.Auf diese Weise optimiertes (≡Si—O)3V ergab identische Spektren und die gleichen chemischen und katalytischen Eigenschaften wie die Oxydations-/Reduktions-Produkte aus wäßrigen Dotierungen von NH4VO3. Dies ist das erste Beispiel für solch eine bemerkenswerte Übereinstimmung von Oberflächen-Verbindungen, die auf unterschiedlichen Reaktionswegen erhalten wurden. Der Nutzen zur Strukturaufklärung wird unterstrichen.Die Bedeutung der Chemilumineszenz als empfindlichster Indikator für identische Oberflächenzustände wird diskutiert, ebenso wie Versuche, „nacktes“ zweibeiniges VII/Si02 und VIII/SiO, darzustellen.
    Notes: Conveniently available transition metal hexamethyldisilazanes (M-HMDS) are described as novel surface reacting agents in ≡Si—O—M type surface compound formation on silicagel. Secondary reaction products ≡Si—O—SiMe3 and ≡Si—N(SiMe3)2 confer “silanized” (hydrophobic) environments which can be removed at 300-400°C. Reactivity of M—N linkages with surface silanols and strained siloxanes can be manipulated by coordinating ligands L (also as solvents) in the molecule.Three legged vanadium(III) surface compounds were obtained directly by thermal activation of V[N(SiMe3)2]3 on SiO2 in neutral or reducing atmospheres. Detailed course of the reaction were monitored by ESCA and Reflectance Spectroscopy. Impregnation from benzene (0.40-0.45 wt. % V) and subsequent heating to 400-800°C (for 1 hr) gave optimized products.The optimized (≡Si—O)3V from V(HMDS)3 was found to have identical spectral, chemical, and catalytical properties as the oxidation/reduction products from NH4VO3 etc. from aq. impregnations including chemiluminescence with O2 at 20°C. This is the first reported example of such remarkable surface product correspondence by different mechanistic pathways and its utility in structural elucidation is emphasized.Importance of chemiluminescence as most sensitive indicator of identical surface states is discussed as well as attempts to produce “naked” two legged VII/SiO2 and VIII/SiO2.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19814831225
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  • 6
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    The dynamic hydrochemical environment of Lake Tiberias, Israel (2005)
    In:  Geochimica et Cosmochimica Acta, Suppl. ; 69, 10, Supplement 1
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    Publication Date: 2020-02-12
    Keywords: 550 - Earth sciences
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  • 7
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    Chemical evolution of saline waters in the Jordan-Dead Sea transform and in adjoining areas (2007)
    In:  International Journal of Earth Sciences
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    Publication Date: 2020-02-12
    Keywords: 550 - Earth sciences
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  • 8
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    Sources of mineralization and salinization of thermal groundwater of Jordan (2006)
    In:  Acta Hydrochimica et Hydrobiologica
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    Publication Date: 2020-02-12
    Description: According to spider patterns five different types of thermal groundwater are distinguishable in Jordan. Each spider diagram comprises groups of elements which characterise soluble minerals of the aquifer such as halite, calcite, and gypsum, and leachable fractions of trace elements such as B, Ba, Br, Y, Cs, Rb, and U. In Jordan, mineralization of groundwater is largely controlled by dissolution of halite, carbonates, gypsum, and leaching diverse K-bearing minerals. Caused by interaction with Neogene basalts, limestones are silicified and mineralogically altered. Groundwater from these aquifers significantly differs in composition from those of the unaltered limestone aquifers. The benefit of spider patterns is that they visualise (i) chemical differences in groundwater from essentially similar aquifer rock such as young, old or thermally altered limestones and (ii) chemical similarities of groundwater produced from different geological formations. In contrast to spider patterns, ionic ratios widely overlap and do not unequivocally allow grouping of groundwater. 34S(sulfate) varies between -4 and +29 . Low values prove the presence of oxidised sulfides either of igneous origin or from sedimentary rocks. The spread of 34S is caused by mixing with marine sulfate. All analysed water from Paleozoic rocks is replenished from younger aquifers. Considerable transaquifer flow exists more or less all over the Jordan territory. Salinization of sandstone-bound water along the rift escarpment is caused by a Na+-K+-SO42--HCO3- brine, whereas the wells Al Umari 1 and Wadi Araba 5 are affected by the presence of a Ca2+-Cl- brine.
    Keywords: 550 - Earth sciences
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  • 9
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    Characterization of the sources of thermal spring- and well water in Jordan by rare earth element and yttrium distribution and stable isotopes of H2O (2006)
    In:  Acta Hydrochimica et Hydrobiologica
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    Publication Date: 2020-02-12
    Description: Four types of thermal groundwater in Jordan were distinguished by Y and rare earth elements (REY) distribution patterns. Complementary to the stratigraphic origin of water in springs or of wells, REY patterns identify either recharge areas covered by basalt, limestones or sandstone, or interaction with basalt-limestone contact zones. This hydrochemical grouping does not always correspond with “common geological knowledge” of the aquifer lithology of the thermal water. Therefore, comparison of the hydrochemical signatures of REY patterns and the lithological source of water yield insight into transaquifer flow. Out of 44 analysed groundwater, 18 indicated down- and 3 upflow of water the latter due to step faults near the Rift system. During transaquifer flow REY patterns of groundwater from basalts and gypsum beds or gypsum-cemented sandstones are not changed by subsequent interaction with limestones, whereas in groundwater originating from dissolution of chalk and limestones REY patterns are adjusted to those typical for gypsum-bearing sediments. Cross plots of d18O vs. d2H reveal essentially two trends. The main trend of water from limestone aquifers define a mixing line of past to recent meteoric water with negligible contributions of Pleistocene water. Some water from Eocene aquifers plot on the local Mediterranean meteoric water line, others plot together with water from sandstone aquifers at enhanced d18O values due to hydrothermal overprinting.
    Keywords: 550 - Earth sciences
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  • 10
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    Hydrochemical processes in the lower Jordan valley and in the Dead Sea area (2007)
    In:  Chemical Geology
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    Publication Date: 2020-02-12
    Description: Changes in the concentrations of major, some minor and trace elements occurring in both surface and groundwater of the lower Jordan River–Dead Sea drainage basin have been investigated in order to identify the characteristics of the regional aquifers and their recharge areas. Spider patterns of elements and rare earth distribution patterns pinpoint the characteristic chemical features of groundwater. As compared to seawater, the high Br/Cl ratios in groundwater are caused either by high Br/Cl ratios in precipitation, by leaching of Br from bituminous matter or by mixing with brines beyond the epsomite stage. The locations of groundwater samples with enhanced B contents coincide with the distribution of gypsum in the beds of the Lisan Formation, which produces water with nearly constant B/SO42− molar ratios. Aeolian distribution of the unconsolidated Lisan sediments influences the B/SO4 ratio in the area of Lake Tiberias and in the Jordan Highlands. The high Gd anomaly in the Dead Sea water is of geologic origin whereas that in the Jordan River and in Nahal (stream) Qidron is largely anthropogenic. The anthropogenic Gd input to the Dead Sea is insignificant compared to the actual amount in the water of the Dead Sea. Hot saline water encountered along the western shores of the Dead Sea with high Gd anomalies indicate that they contain large amounts of ancient Dead Sea water that mix (as hot ascending brines) with fresh water. The recharge area of groundwater in the lower Jordan Valley extends largely over limestone and dolomite outcrops of the Upper Cretaceous Judea Group. Weathering of locally underlying Lower Cretaceous volcanics in the area of Pezael–Beqaot, and Argaman yield groundwater with δ34S(SO42−) values ranging from − 2 to + 4‰. The presence of sulphide-bearing bodies in this area is attested to magnetic anomalies detected at depths of several kilometres. δ34S(SO42−) indicates very deep groundwater circulation. High δ34S(SO42−) 〉 15‰ is typical for marine sulphates from the Judea and Avedat Group limestone. The springs located along the northwestern shore of the Dead Sea discharge water replenished on the eastern Judea Mountains. The increase in the salinity of this water is due to brines flushed from sediments and from adjacent sedimentary rocks, which host entrapped brines from the precursors of the Dead Sea formed during the late stages of Lake Lisan. Fresher water flushes out these residual brines as a result of falling sea level. Salinity increase in groundwater is also affected by the ascent of deep-seated hot brines from pre-Sedom periods along the Rift faults. Calculations of mixing between fresh and highly saline end-members show that leaching of anhydrite from sediments, precipitation of calcite, formation of dolomite, albitization of plagioclase and ion exchange with abundant clay minerals control the major-element composition of the saline groundwater.
    Keywords: 550 - Earth sciences
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