Do Perchlorate and Triflate Anions Bind to the Uranyl Cation in an Acidic Aqueous Medium? A Combined EXAFS and Quantum Mechanical Investigation
✍ Scribed by Laurent Sémon; Christian Boehme; Isabelle Billard; Christoph Hennig; Klaus Lützenkirchen; Tobias Reich; André Roßberg; Isabelle Rossini; Georges Wipff
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 146 KB
- Volume
- 2
- Category
- Article
- ISSN
- 1439-4235
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✦ Synopsis
Structural properties of uranyl cations in acidic aqueous perchlorate and triflate solutions were investigated using uranium L III -edge extended X-ray absorption fine-structure spectroscopy (EXAFS) in conjunction with quantum mechanical calculations of gas-phase model complexes. EXAFS spectra were measured in aqueous solutions of up to 10 M triflic and 11.5 M perchloric acid, as well as mixtures of perchloric acid and sodium perchlorate. In no case is the perchlorate anion coordinated to UO 2 2 . The number of equatorial water molecules bound to UO 2 2 is always about five. In the case of the 10 M CF 3 SO 3 H solution, an inner-sphere complex-ation of the triflate is observed with a U À S radial distance of 3.62 . These results are in qualitative agreement with quantum mechanical calculations of model uranyl complexes, according to which the interaction energies of anions follow the order perchlorate triflate ( nitrate.