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  • 1990-1994  (3)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 585 (1990), S. 113-120 
    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. XL. On the Nibium Oxide Flurides NiNb14O35F2 and CoNb14O35F2Crystals of NiNb14O35F2 and CoNb14O35F2 were prepared from mixtures M2+F2/Nb2O5 = 1:7 (M2+ = Ni, Co) by migration in a gradient of temperature (for example 1200 → 1100°C). In accordance with the isostructural compound MgNb14O35F2 they have a block structure consisting of edge-sharing building elements (blocks) of [3 × 5] M-X-octahedra (X = O, F) in a monoclinic arrangement. The data for the unit cells of NiNb14O35F2 (CoNb14O35F2) resulting from the evaluation of the Guinier diagrams are a = 20.62 (20.65), b = 3.83 (3.83), c = 19.25 (19.27) Å, β = 108.41 (108.35)°. The images obtained from HRTEM investigations show only few faults of the ideal structure.
    Notes: NiNb14O35F2 und CoNb14O35F2 ließen sich aus den Gemengen M2+F2/Nb2O5 = 1:7 (M2+ = Ni, Co) über eine Wanderung im Temperaturgradienten (z. B. 1200 → 1100°C) in kristalliner Form gewinnen. Wie bei der isotypen Verbindung MgNb14O35F2 liegen Blockstrukturen vor, deren kantenverknüpfte Bauelemente (Blöcke) aus [3 × 5] M-X-Oktaedern (X = O, F) monoklin angeordnet sind. Die Auswertung der Guinieraufnahmen ergab für NiNb14O35F2 (CoNb14O35F2) die Gitterkonstanten: a = 20,62 (20,65), b = 3,83 (3,83), c = 19,25 (19,27) Å, β = 108,41 (108,35)°. HRTEM-Untersuchungen lieferten Abbildungen einer nur wenig gestörten Realstruktur.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 580 (1990), S. 95-102 
    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. XXXVIII. Quaternary Niobium Oxide Fluorides of Cadmium and Manganese with LiNb6O15F structureFor the first time we observed an occupation of the canals in the LiNb6O15F structure by bivalent metal ions. We obtained wellshaped crystals of MxNb6(O, F)16 (M = Cd, Mn) by heating mixtures of MF2 and Nb2O5. CdxNb6(O, F)16 (MnxNb6(O, F)16) crystallizes in the orthorhombic space group Pmma with a = 16.686 (16.677), b = 3.951 (3.952) and c = 8.907 (8.902) Å. The structure of the cadmium compound was refined to give R = 3.33% and Rw = 2.90%. The resulting formula for the investigated crystal was Cd0.25Nb6O14.5F1.5.
    Notes: Erstmals fanden wir Beispiele für eine Besetzung der Kanäle in der LiNb6O15F-Struktur mit zweiwertigen Metallionen. Gut ausgebildete Kristalle der beiden Verbindungen MxNb6(O, F)16 mit M = Cd bzw. Mn wurden durch Erhitzen von Gemengen aus MF2 und Nb2O5 dargestellt. CdxNb6(O, F)16 (MnxNb6(O, F)16) kristallisiert orthorhombisch in der Raumgruppe Pmma mit a = 16,686 (16,677), b = 3,951 (3,952) und c = 8,907 (8,902) Å. Die Struktur der Cadmiumverbindung wurde bis zu R = 3,33% bzw. Rw = 2,90% verfeinert. Die Zusammensetzung des untersuchten Kristalls ergab sich zu Cd0,25Nb6O14,5F1,5.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    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 Inorganie Non-stoichiometric Compounds. XXXIX. X-Ray Structure Analysis and Electronmicroscopical Investigation of MnxNb6(O, F)16The structure of MnxNb6(O, F)16, which is concerning the network of the Nb-X-Polyhedrons (X = O, F) isostructural with LiNb6O15F, was refined to give R = 7.2% and Rw = 2.96%. The resulting formula for the investigated crystal was Mn0.17Nb6O14.34F1.66. Only one of the two possible sites in the canals of the structure is occupied by Mn. The investigation with high resolution electron microscopy yielded pictures which indicate the pentagonal columns as dark contrasts.
    Notes: Die Strukturparameter des Mangannioboxidfluorids MnxNb6(O, F)16, das hinsichtlich des Nb-X-Polyedergerüstes (X = O, F) mit LiNb6O15F isotyp ist, wurden bis zu R = 7,2% bzw. Rw = 2,96% verfeinert. Die Zusammensetzung des untersuchten Kristalls ergab sich zu Mn0,17Nb14,34F1,66. Nur eine der beiden möglichen Lagen in den Kanälen der Struktur ist mit Mn besetzt. Die elektronenmikroskopische Untersuchung ergab hochaufgelöste Abbildungen, die die Nb-X-Polyeder als dunkle Kontraste in der Projektion längs [010] erkennen lassen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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