Direct observation of fractional change of niobium ionic species in a solution by means of X-ray absorption fine structure spectroscopy
Article first published online: 20 APR 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Special Issue: Novel methods of X-ray generation
Volume 41, Issue 4, pages 259–263, July/August 2012
How to Cite
Kubouchi, Y., Hayakawa, S., Namatame, H. and Hirokawa, T. (2012), Direct observation of fractional change of niobium ionic species in a solution by means of X-ray absorption fine structure spectroscopy. X-Ray Spectrom., 41: 259–263. doi: 10.1002/xrs.2390
- Issue published online: 21 JUN 2012
- Article first published online: 20 APR 2012
- Manuscript Accepted: 19 FEB 2012
- Manuscript Revised: 8 FEB 2012
- Manuscript Received: 24 DEC 2011
- DFT calculation;
Local coordination of niobium oxalate in oxalic acid solutions was investigated by Nb L3-edge X-ray absorption near edge structure (XANES) spectroscopy that was sensitive to the coordination environment of X-ray absorbing atoms. The Nb L3-edge XANES spectra were measured from solutions of difference pH, and the solution was composed of different molar fractions of NbO(C2O4)2H2O− and NbO(C2O4)33−. The lower energy shift of the spectral peak was observed with the lower pH that was attributed to the greater fraction of NbO(C2O4)2H2O−. The spectral shape was different from those of reference samples representing tetrahedral and octahedral coordination, and the lower symmetry of niobium site was confirmed. The XANES spectra of two ionic species were simulated with the density functional theory calculations, and the mixture of these spectra demonstrated the peak shift caused by the change of solution pH. Copyright © 2012 John Wiley & Sons, Ltd.