Crystal structure and spectral characterization of La-2(CO3)(3) center dot 5H(2)O - an industrially relevant lanthanide carbonate

Ciftci, Esengul; Podjaski, Filip; Gouder, Andreas; Lotsch, Bettina V.; Dinnebier, Robert E. and Bette, Sebastian (2022): Crystal structure and spectral characterization of La-2(CO3)(3) center dot 5H(2)O - an industrially relevant lanthanide carbonate. In: Zeitschrift für Anorganische und Allgemeine Chemie, Vol. 648, No. 23, e202200218

Abstract

The conversion of La2O3 with HCl, subsequent neutralization and precipitation using (NH4)(2)CO3 in an industrial process leads to the previously unknown La-2(CO3)(3) center dot 5H(2)O. The phase was characterized by X-ray powder diffraction leading to an averaged crystal structure model, thermal analysis, vibrational and optical spectroscopy. La-2(CO3)(3) center dot 5H(2)O crystallizes in space group Pbca(61) with a=9.0167(4) angstrom, b=12,842(3) angstrom, c=9.6331(4) angstrom and V=1115.4(3) angstrom(3). The structure consists of infinity(2){(La(CO3)(4/4)(+)} zig zag layers and a highly disordered interlayer space occupied by water molecules and carbonate anions. Partially occupied water-related oxygen positions theoretically allow for a flexible hydrate water content La-2(CO3)(3) center dot xH(2)O, with x ranging from 1.5 to 5.0. Although a strong structural relationship between La-2(CO3)(3) center dot 5H(2)O and La-2(CO3)(3) center dot 8H(2)O and similar substance properties were found, the title compound cannot be obtained by partial dehydration of the octahydrate. Instead, both lanthanum carbonate hydrates transform into strongly disordered La-2(CO3)(3) in a one-step dehydration process.

• Item Type: Journal article
• Faculties: Chemistry and Pharmacy > Department of Chemistry
• Subjects: 500 Science > 540 Chemistry
• ISSN: 0044-2313
• Language: English