X-ray Absorption near Edge Structure and Extended X-ray Absorption Fine Structure Analysis of Fe(II) Aqueous and Acetone Solutions

Abstract

X-ray absorption spectroscopy measurements were used to determine the structure of the first coordination shell of Fe(II) ions in aqueous and acetone based solutions. Extended X-ray absorption fine structure analysis coupled with ab initio X-ray absorption near edge structure calculations confirms the octahedral coordination of the iron ion in water based solution. Data collected for acetone rich solutions can be reproduced assuming coexistence of the octahedral Fe(H(2)O)(6)(2+) and tetrahedral [FeCl(4)](2-) complexes. Distortion of the tetrahedral coordination of ion was detected in some of the acetone based solutions.

Fe(II) sorption on pyrophyllite: Effect of structural Fe(III) (impurity) in pyrophyllite on nature of layered double hydroxide (LDH) secondary mineral formation

“…Sorption sample RSFs show the first Fe coordination shell at ~1.6 Å (uncorrected for phase shift), which represent O ligands in the first shell surrounding Fe. This shell was fitted with 5.0-6.3 O atoms at radial distance of 2.05-2.11 Å (Table1), which is consistent with octahedral coordination of the O atoms around the central Fe(II) atom(Elzinga, 2012; Huminicki and Hawthorne, 2003;Olszewski et al, 2011;Parise et al, 2000;Shannon, 1976). A growth in the second coordination shell (~2.8 Å) of the sorption samples can be observed with an increase in reaction time for both Fe and Al,…”

Structure of Iron Ions in Some Acetone Based Electrolytes

“…The Mössbauer spectra show unambiguously coexistence of Fe(H 2 O) 6 2+ and Fe(III) species (Figure ). The first-principle analysis of XAS spectra, performed under assumptions that octa- and tetrahedral local environments coexist, agree well with the observed crossing of the XAS oscillations (Figure ). Ions with octahedral environment were not observed in Raman experiments; however, combined measurements of samples prepared from FeCl 2 and FeCl 3 allow quantitative fractions of tetra- and octa-coordinated Fe ions to be obtained, in good agreement with the XAS and Mössbauer results.…”

“…In the case of solutions rich in acetone, the experimental data were reproduced assuming that the majority of iron ions form complexes with tetrahedral Cl − arrangement and the rest octahedral Fe(H 2 O) 6 2+ . 6 The obtained values of the structural parameters were in good agreement with previously reported values for those complexes. 1,7−9 The samples for experiments 6 were prepared from FeCl 2 with sufficient care to avoid oxidation of Fe(II) by oxygen, either atmospheric or dissolved in the solvents, and the results of X-ray analysis were explained consistently assuming the presence of Fe(II) ions only.…”

Investigating DNA Radiation Damage Using X-Ray Absorption Spectroscopy

“…This may be due to limitations of the theoretical calculations, such as many body effects (36) or the precision of the Debye-Waller factor (37). Other examples of FDMNES calculations that reproduced the experimental data well can be found in (38)(39)(40)(41). Because the PO 4 geometry in DNA changes slightly depending on the actual P position in the DNA strand, the calculated spectrum represents an average of calculated XAS spectra for all 18 P-sites in PDB structure 1D23.…”