Journalartikel

Jahr der Veröffentlichung: 1993

Seiten: 409-415

Zeitschrift: Journal of Inorganic and General Chemistry

Bandnummer: 619

Heftnummer: 2

ISSN: 0044-2313

DOI Link: https://doi.org/10.1002/zaac.19936190228

Verlag: Wiley

Abstract: 

Ternary tantalates and niobates of the hexagonal structure-type A(n+1)/mm+M3n+1O8n+3 (A(m+) = Na+, Cu+, Ag+,...; M = Ta, Nb) were heated with surplus CuCl, PbCl2, LaCl3 or BiCl3 (for example T = 700-degrees-C in case of PbCl2).

In some of these cases it was possible to exchange the A(m+)-ions for the cations of the halide melts by maintaining the basic structure (for example: Cu3Ta7O19 + BiCl3 = BiTa7O19 + 3CuCl). In different reactions the stack along the crystallographic c-axis and furthermore the proportion O/M (for example: 7Cu5Ta11O30 + 35/2PbCl2 = 11Pb1,5Ta7O19 + PbO + 35CuCl) changed.

Nevertheless, it was not possible to substitute cations of the halide melt for A(m+)-ions in every direction (not possible for example: LaTa7O19 + BiCl3).

When CuCl- and PbCl2-melt were added to Ag2Ta4O11 and Na2Nb4O11, these niobates showed exange reactions by changing their structure completely. If BiCl3-melt was added, these niobates decayed while forming B-Nb2O5.

The new hexagonal tantalates Pb1,5Ta7O19 (a = 6,2411(7) angstrom; c = 19,977(3) angstrom) and PbTa4O11 (low-temperature modification; a = 6,2364(3) angstrom; c = 36,851(3) angstrom) were the first representatives of the structure-type A(n+1)/mm+M3n+1O8n+3 with A(m+) = Pb2+, which were found in a reaction with PbCl2 (Cu3Ta4O19 + 3/2PbCl2 = Pb1,5Ta7O19 + 3CuCl; Ag2Ta4O11 + PbCl2 = PbTa4O11 + 2AgCl). These two compounds, which are probably metastable, could only be achieved by exange reactions of ions.

Harvard-Zitierstil: STEMMER, W. and GRUEHN, R. (1993) EXCHANGE-REACTIONS OF TERNARY TANTALATES AND NIOBATES WITH HALIDE MELTS - A WAY TO NEW LEAD TANTALATES, Zeitschrift für anorganische und allgemeine Chemie = Journal of Inorganic and General Chemistry, 619(2), pp. 409-415. https://doi.org/10.1002/zaac.19936190228

APA-Zitierstil: STEMMER, W., & GRUEHN, R. (1993). EXCHANGE-REACTIONS OF TERNARY TANTALATES AND NIOBATES WITH HALIDE MELTS - A WAY TO NEW LEAD TANTALATES. Zeitschrift für anorganische und allgemeine Chemie = Journal of Inorganic and General Chemistry. 619(2), 409-415. https://doi.org/10.1002/zaac.19936190228