Local structure of molten LaCl 3 by K-absorption edge XAFS

• Published in: Journal of molecular structure Vol. 641; no. 1; pp. 71 - 76
• Main Authors: Okamoto, Yoshihiro, Shiwaku, Hideaki, Yaita, Tsuyoshi, Narita, Hirokazu, Tanida, Hajime
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2002
• Subjects: Coordination; Local structure; Molten salt; X-ray absorption fine structure; Local structure; Coordination; X-ray absorption fine structure; Molten salt
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/S0022-2860(02)00329-0

The local structure of molten LaCl 3 was investigated by X-ray absorption fine structure of the La K-edge. The nearest La 3+–Cl − distance and coordination number were 2.89±0.01 Å and 7.4±0.5 from the curve fitting of the first peak in the Fourier transform magnitude |FT|. The coordination number larger than 6 suggests that the local structure of molten LaCl 3 is not a simple octahedral coordination (LaCl 6) 3−, but 7-fold (LaCl 7) 4− and/or 8-fold (LaCl 8) 5− complexes. The first La 3+–La 3+ distance, of which correlation was observed as a weak second peak in the |FT|, was evaluated to be 4.9 Å. It suggests that the distorted corner-sharing connection of the complex species is predominant in the melt, in contrast with molten YCl 3 in which the edge-sharing connection of the 6-fold (YCl 6) 3− mainly exists.