The quantitative Jahn-teller distortion of the Cu2+ site in aqueous solution by xanes spectroscopy

García, J.; Benfatto, M.; Natoli, C. R.; Bianconi, A.; Fontaine, A.; Tolentino, H.

doi:10.1016/0301-0104(89)80095-3

Cited by 91 publications

(55 citation statements)

References 22 publications

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“…These features in the derivatized XANES spectra resemble those observed for Cu-HS complexes (Frenkel and Korshin 1999). In the latter case, the splitting of the corresponding derivative XANES spectra was attributed to the tetragonal distortion of the CuO 6 octahedron (Garcia et al 1989;Palladino et al 1993). We will present more discussion on this matter in the following sections.…”

Section: Xanes Datasupporting

confidence: 57%

Studies of Cu(II) in soil by X-ray absorption spectroscopy

Frenkel¹,

Korshin²

2001

Can. J. Soil. Sci.

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Frenkel, A. I. and Korshin, G. V. 2001. Studies of Cu(II) in soil by X-ray absorption spectroscopy. Can. J. Soil Sci. 81: 271-276. Based on original data for copper, this paper evaluates the use and advantages of X-ray absorption fine structure (XAFS) in studies of heavy metals in soils. The structural parameters of the Cu 2+ target were quantified for soil exposed to copper and the same soil eluted with 0.1 M HCl. Experimental data were obtained using synchrotron sources of second and third generations. X-ray absorption near edge structure (XANES) indicated that the copper in both samples is likely to be predominantly bound by oxygen-containing functional groups. Extended X-ray absorption fine structure (EXAFS) analysis showed that the equatorial Cu-O distances were similar to those seen for Cu 2+ -humic complexes in aqueous solutions, but the axial distances for both samples were longer than in water. In the axial direction, this may indicate a type of ligation dissimilar to that in solutions. The magnitude of the mean square deviation of the axial Cu-O distance in the 0.1 M HCl eluted sample indicated a stronger bond compared with that in the sample containing both extractable and tightly bound copper. The results indicate that careful examination of structural data for sequentially eluted soils in combination with the development of new radiation sources to improve the sensitivity and quality of the data are likely to improve insight into the nature of interactions between heavy metals and soil.Key words: Soil, copper, humic, speciation, extended X-ray absorption fine structure, X-ray absorption near edge structure Mots clés: Sol, cuivre, humique, espèces chimiques, EXAFS, XANES X-Ray Absorption Fine Structure spectroscopy is an advanced structural technique based on the use of high intensity synchrotron radiation to measure the X-ray absorption coefficient of a material as a function of the X-ray energy. The interpretation of XAFS spectra provides quantitative information regarding the short-range atomic structure around the target element in the sample.The fine structure in the XAFS spectrum originates from the oscillatory nature of the wave function of the photoelectron ejected from the target atom in the photoabsorption process. The fine structure in the absorption coefficient starts at ca. 40 eV and extends ca. 1000 eV past the absorption edge. For these energies, single and multiple scatterings of the photoelectron by its nearest neighbors define the behavior of the X-ray absorption coefficient, which, due to its nature, contains the information about the identity and coordination numbers of the surrounding atoms, as well as about relevant distances and their disorders. The method of XAFS, which studies the absorption coefficient in the discussed range of energies, is called Extended X-Ray Absorption Fine Structure (EXAFS). The X-ray absorption near edge structure (XANES) spectroscopy is an allied but independent method that examines the data in the energy region from the Fermi level up to 40 eV past t...

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Section: Xanes Datasupporting

confidence: 57%

Studies of Cu(II) in soil by X-ray absorption spectroscopy

Frenkel¹,

Korshin²

2001

Can. J. Soil. Sci.

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“…Moreover, the XANES region also contains information about electron transitions. It was found that the a peak intensity is influenced by the degree of axial distortion [25] and by the covalence of the equatorial ligands bonded to the Cu II atom. [26] The source of the a electron transition has been attributed to a shakedown effect, whereby the final electron state is lower in energy than the direct 1s 3 4p transition.…”

Section: Resultsmentioning

confidence: 98%

Molecular Scale Speciation of First‐Row Transition Elements Bound to Ligneous Material by Using X‐ray Absorption Spectroscopy

Merdy

Aplincourt

2003

Chemistry A European J

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To develop a solid scientific basis for maintaining soil quality and formulating effective remediation strategies, it is critical to determine how environmentally-important trace metals are sequestered in soils at the molecular scale. The speciation of Mn, Fe and Cu in soil organic matter has been determined by synchrotron-based techniques: extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES). We show the structural similarity between the surface complexes of Mn(II), Fe(III) and Cu(II). These cations are bound to the surface through oxygen atoms. Each one presents a more or less tetragonal-distorted octahedral geometry. The use of X-ray absorption spectroscopy provides a relevant method for determining trace-metal speciation in both natural and contaminated environmental materials.

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“…A primary question that arises from the doublechannel phenomena is whether the EXAFS fitting procedure based on the assumption of a single channel, as already done by many research groups for the last 30 years, 5,6,17,19,21 would be affected of some bias as a consequence of neglecting the existence of a second channel absorption. If this was the case a new question would appear: Might the splitting of the Cu-O distances, which supports the Jahn-Teller distortion of Cu͑II͒ hydrate, be an artifact of the fitting procedure to compensate for the lack of the second absorption channel?…”

Section: Figmentioning

confidence: 99%

“…21 Sixteen years later, the debate is far from being closed. This controversy on the structure of Cu͑II͒ hydrate in solution is a good test of the limits of the capability of x-rayabsorption spectroscopy to solve the local structure around ions in aqueous solution, since different analysis performed on data recorded by using the same experimental technique does not converge towards the same conclusions.…”

Section: Introductionmentioning

confidence: 99%

The hydration of Cu2+: Can the Jahn-Teller effect be detected in liquid solution?

Chaboy

Muñoz‐Páez

Merkling

et al. 2006

The Journal of Chemical Physics

112

125

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The long elusive structure of Cu͑II͒ hydrate in aqueous solutions, classically described as a Jahn-Teller distorted octahedron and recently proposed to be a fivefold coordination structure ͓Pasquarello et al., Science 291, 856 ͑2001͔͒, has been probed with x-ray-absorption spectroscopy by performing a combined theoretical and experimental analysis. Two absorption channels were needed to obtain a proper reproduction of the x-ray-absorption near-edge structure ͑XANES͒ region spectrum, as already observed in other Cu͑II͒ complexes ͓Chaboy et al., Phys. Rev. B 71, 134208 ͑2005͔͒. The extended x-ray-absorption fine-structure ͑EXAFS͒ spectrum was analyzed as well within this approach. Quite good reproductions of both XANES and EXAFS spectra were attained for several distorted and undistorted structures previously proposed. Nevertheless, there is not a clearly preferred structure among those including four-, five-, and sixfold coordinated Cu͑II͒ ions. Taking into account our results, as well as many more from several other authors using different techniques, the picture of a distorted octahedron for the Cu͑II͒ hexahydrate in aqueous solution, paradigm of the Jahn-Teller effect, is no longer supported. In solution a dynamical view where the different structures exchange among themselves is the picture that better suits the results presented here.

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The quantitative Jahn-teller distortion of the Cu2+ site in aqueous solution by xanes spectroscopy

Cited by 91 publications

References 22 publications

Studies of Cu(II) in soil by X-ray absorption spectroscopy

Studies of Cu(II) in soil by X-ray absorption spectroscopy

Molecular Scale Speciation of First‐Row Transition Elements Bound to Ligneous Material by Using X‐ray Absorption Spectroscopy

The hydration of Cu2+: Can the Jahn-Teller effect be detected in liquid solution?

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