ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 11
    Electronic Resource
    Electronic Resource
    Beiträge zur Untersuchung anorganischer nichtstöchiometrischer verbindungen. XV. Weitere metastabile Nb2O5-Modifikationen, Produkte der langsamen Oxydation von NbOx-Phasen (1982)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 484 (1982), S. 98-123 
    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 Investigation of Inorganic Non-stoichiometric Compounds. XV. Some Further Metastable Nb2O5-Modifications, Products of the Slow Oxidation of the NbOx PhasesIf in contrast to previous investigations the blue-black NbOx phases (2.4 〈 x 〈 2.5) are not oxidized in air, but in a rarefied oxygen atmosphere or with steam, five further metastable Nb2O5 forms can be obtained in addition to the numerous already known Nb2O5 modifications. Nb12O29 (mon. and orh.) and Nb47O116 lead to one new Nb2O5 form each. Nb22O54 yields two new Nb2O5 modifications. It can be deduced from the thermal behaviour that in addition to unexspected transitions between the known and the new metastable modifications in all cases H-Nb2O5 appears as final product at high temperature. The electron optical investigation of the new oxidation products of Nb12O29 (mon. and orh.) shows that their structures are determined by R-type tunnels as the characteristic structure element. By this they clearly differ from the already known oxidation products. With this for the first time sodium free niobium oxide structures occur whose structural concept is substantially shaped by R-type tunnels which are known from NaNb13O33.
    Notes: Oxydiert man die blauschwarzen NbOx-Phasen (2,4 〈 x 〈 2,5) im Unterschied zu früheren Untersuchungen nicht an der Luft, sondern in verdünnter Sauerstoffatmosphäre oder mit Wasserdampf, so werden zusätzlich zu den zahlreichen bisher bekannten Nb2O5-Modifikationen fünf weitere metastabile Formen von Nb2O5 erhalten. Nb12O29 (mon. und orh.) geht in je eine, Nb22O54 in zwei und Nb47O116 in eine neue Nb2O5-Form Über. Wie das thermische Verhalten zeigt, tritt außer unerwarteten Übergängen zwischen den bekannten und den neuen metastabilen Modifikationen in allen Fällen als Endstufe bei hoher Temperatur H-Nb2O5 auf.Aus der elektronenoptischen Untersuchung der neuen Oxydationsprodukte von Nb12O29 (mon. und orh.) geht hervor, daß ihr Aufbau durch R-Typ-Lücken als charakteristisches Strukturelement bestimmt ist, so daß sie sich von den bisher bekannten Oxydationsprodukten strukturell klar unterscheiden. Damit liegen erstmals Na-freie Nioboxidstrukturen vor, an deren Aufbau die von NaNb13O33 bekannten R-Typ-Lücken maßgeblich beteiligt sind.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19824840108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Beiträge zur Untersuchung anorganischer nichtstöchiometrischer Verbindungen. XX. Metastabile Oxydation von Mischkristallreihen - ein Zugang zu W-reichen Blockstrukturen im System Nb2O5/WO3 (1982)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 489 (1982), S. 240-240 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19824890129
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Beiträge zur Untersuchung anorganischer nichtstöchiometrischer Verbindungen. XX. Metastabile Oxydation von Mischkristallreihen  -  ein Zugang zu W-reichen Blockstrukturen im System Nb2O5/WO3Professor Harald Schäfer zum 70. Geburtstage am 10. Februar 1983 gewidmet (1983)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 497 (1983), S. 56-64 
    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 Investigation of Inorganic Non-stoichiometric Compounds. XX. Metastable Oxidation of a Series of Solid Solutions  -  an Access to W-rich Block Structures in the System Nb2O5/WO3The characteristical region of existence of block structures with building elements that are limited in size in two directions ends in the system Nb2O5/WO3, as was shown by previous investigations, under conditions of equilibrium at a maximum value of 2.654 O/ΣM. For the occurring phases with the ratios Nb2O5: WO3 = 6:1, = 7:3, = 8:5 and = 9:8 as well we now were successful in substituting W for Nb. The original block structure and the corresponding ratio O/ΣM were preserved. The “9:8”-phase W4/4[Nb18W7O69], for example, forms solid solutions W4/4[Nb11W14O69] leaving the size of the building elements ([5 times; 5] blocks) unchanged. Hereby the ratio W/Nb is drastically enhanced from 0.444 to 1.364. By metastable oxidation of these solid solutions at temperatures of about 500°C, for instance in air, one comes back to the system Nb2O5/WO3. In this way the region of existence of block structures could be expanded far beyond the limit at 2.654 O/ΣM to higher W/Nb values.
    Notes: Das charakteristische Existenzgebiet der Blockstrukturen mit zweidimensional begrenzten Bauelementen endet im System Nb2O5/WO3, wie bereits frühere Untersuchungen gezeigt haben, unter Gleichgewichtsbedingungen bei einem Maximalwert von 2,654 O/O/ΣM (M = Nb, W). Es gelang nun, in den mit den Verhältnissen Nb2O5: WO3 = 6:1, 7:3, 8:5 sowie 9:8 auftretenden Phasen im weiten Umfang Nb durch W zu substituieren, wobei ihre ursprüngliche Blockstruktur und das jeweilige Verhältnis O/ΣM erhalten blieben. So bildet z. B. die «9:8»-Phase W4/4[Nb18W7O69] bei unveränderter Größe der Bauelemente ([5 × 5]-Blöcke) einen Mischkristall W4/4[Nb11W14O69]; das Verhältnis W/Nb wird damit drastisch von 0,444 auf 1,364 erhöht. Durch metastabile Oxydation der so erhaltenen Mischkristalle bei Temperaturen um 500°C, z. B. an der Luft, gelangt man in das System Nb2O5/WO3 zurück. Das Existenzgebiet der Blockstrukturen konnte in dieser Weise bis weit über die Grenze bei 2,654 O/ΣM hinaus zu höheren W/Nb-Werten erweitert werden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19834970205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Raman spectra of copper(I), silver(I) and gold(I) cyanides in aqueous solutions of sodium thiosulphate (1985)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 16 (1985), S. 272-279 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Systems of copper(I), silver(I) and gold(I) cyanides dissolved in aqueous solutions of sodium thiosulphate in different molar ratios have been studied by Raman Spectroscopy. CuCN dissolves completely in aqueous thiosulphate solution in a 1:3 CuCN to S2O32- ratio, forming only mixed cyanothiosulphate species. No evidence was found for the formation of Cu (CN)2-, Cu(CN)32- or Cu(CN)43-. The mixed cyano copper complex was isolated as a white solid insoluble in water and most other solvents. The solid probably consists of a polymeric structure with bridging cyanide and thiosulphate. AgCN dissolves completely in aqueous thiosulphate solution in a 1:1 AgCN to S2O32- ratio, resulting in the formation of Ag(CN)2- and Ag(S2O3)23- species. As the concentration of thiosulphate increases Ag(CN)2(S2O3)3- and Ag(CN)2(S2O3)25- are formed. There is strong evidence for the existence of bridging silver thiosulphate complex in solutions of low S2O32- concentration. AuCN dissolves completely in aqueous thiosulphate solution in a 1:2 AuCN to S2O32- ratio, forming Au(CN)2-, Au(CN) (S2O3)2- and Au(S2O3)23-. No evidence was found for the formation of species of higher coordination number on increasing the concentration of S2O32-, which indicates that the linear two-coordinate gold complexes are the most stable.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250160410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...