Multi-spectroscopic study of Fe(II) in silicate glasses: Implications for the coordination environment of Fe(II) in silicate melts

Structure of (FexCa1−xO)y(SiODrewitt1, Sanloup2, Bytchkov3 et al. 2013Phys. Rev. B

“…12,13,24,29,31,32,34 In general, ferrous iron (Fe 2+ ) tends to occupy a distribution of four, five, and sixfold coordination sites with oxygen, where interpretations of x-ray absorption spectroscopy (XAS) measurements suggest that four and fivefold coordinated Fe sites dominate. 22,23,25,30,34,36 This result is, however, in contrast to Raman and optical absorption spectra, which report Fe 2+ in sixfold coordination. 6,7,9,17,18,42 By comparison, very little direct information is available on the local coordination environment in iron silicate melts due to the difficulty of performing experiments at high temperatures.…”

“…23,30,46,47 Our results instead support predictions from optical and Raman spectra that suggest a significant fraction of sixfold coordinated Fe 2+ polyhedra. 6,17,18 Keppler 17 argued that the EXAFS evidence for Fe in tetrahedral coordination in silicate melts and glasses may be affected by positional disorder effects yielding significantly too short Fe-O distances and coordination numbers if the Fe cations occupy highly distorted octahedral sites.…”

Structural Characterization of FeO–SiO₂–V₂O₃ Slags Using Molecular Dynamics Simulations and FT-IR Spectroscopy

“…[13][14][15][16][17][18] Meanwhile, molecular dynamics (MD) simulation, as a approach complementary to experimental techniques, has also been applied to investigate the structure and properties of ferrosilicate systems. 14,19,20) Both experimental and simulation work have suggested that SiO 4 tetrahedron is the fundamental building block for silicates, while the structural behavior of Fe 2 + is still debated.…”

“…Fe 2 + adopts 4-, 5-or 6-fold coordination were found in silicate melts and glasses under different silicate composition, temperature, pressure and f O 2 . [14][15][16]18,[21][22][23][24][25] Notwithstanding, in most cases FeO acts as a network modifier which offers O 2 − and thus depolymerizes the silicate network. 4,15) Although there are numerous studies on the structural characterization and physicochemical properties of V-containing materials, rather limited information is available on the structural configurations of trivalent V in silicate melts and glasses.…”

Structure of the FeBTC Metal–Organic Framework: A Model Based on the Local Environment Study

“…21 More generally, the area of the pre-edge peak normally increases when the occupancy of d-orbital decreases and when the degree of symmetry decreases. 22 Notably, the relationship between geometry and pre-edge absorption shape was extensively analyzed in studies on volcanic glasses, with the following results: for Fe(III) in an octahedral site, two different electronic transitions are foreseen to stem from the 1s core orbital with an expected energy separation of about 1.5 eV (Δo) due to the octahedral crystal field. 20 On the contrary, the energy separation due to tetrahedral crystal field (Δt) is sensibly smaller, and predicted to be 4/9Δo corresponding to about 0.67 eV.…”