Journalartikel

Autorenliste: HOFMANN, R; GRUEHN, R

Jahr der Veröffentlichung: 1991

Seiten: 105-117

Zeitschrift: Journal of Inorganic and General Chemistry

Bandnummer: 602

Heftnummer: 11

ISSN: 0044-2313

DOI Link: https://doi.org/10.1002/zaac.19916020112

Verlag: Wiley

Abstract: 
Two new ternary compounds, LaNb7O19 and CeNb7O19, could be prepared and characterized. At temperatures about 900-degrees-C already decomposition of both compounds will be initiated, but at lower temperatures (800-degrees-C) no reaction between the binary components occured. Single crystals could be obtained by chemical transport reactions (T2 --> T1; T2 = 800-degrees-C; T1 = 780-degrees-C). Chlorine for mineralization or as transport agent is absolutely indispensable for preparation. Single crystal investigations on LaNbO19 (R = 4.4%; R(w) = 4.19%) result in the trigonal space group P3. The cell dimensions are a = 6.2531(2) angstrom; c = 20.0685(10) angstrom; Z = 2. The structure can be described as to be build up by layers of 8-coordinated La and 6-coordinated Nb, alternating with layers of edge-sharing pentagonal NbO7-bipyramids. Corresponding to the unusual sequence of layers the structure of LnNb7O19 (Ln = La, Ce) is the first example of a trigonal member of a family of structures, which has been described in detail by Jahnberg. The most examples are represented by tantalates, but only a few niobates related to these structures are known.

Harvard-Zitierstil: HOFMANN, R. and GRUEHN, R. (1991) PREPARATION AND STRUCTURE OF LNNB7O19 (LN = LA, CE), Zeitschrift für anorganische und allgemeine Chemie = Journal of Inorganic and General Chemistry, 602(11), pp. 105-117. https://doi.org/10.1002/zaac.19916020112

APA-Zitierstil: HOFMANN, R., & GRUEHN, R. (1991). PREPARATION AND STRUCTURE OF LNNB7O19 (LN = LA, CE). Zeitschrift für anorganische und allgemeine Chemie = Journal of Inorganic and General Chemistry. 602(11), 105-117. https://doi.org/10.1002/zaac.19916020112