@article{fdi:010053495,
  title = {{V} oxidation state in {F}e-{T}i oxides by high-energy resolution fluorescence-detected {X}-ray absorption spectroscopy},
  author = {{B}ordage, {A}. and {B}alan, {E}tienne and de {V}illiers, {J}. {P}. {R}. and {C}romarty, {R}. and {J}uhin, {A}. and {C}arvallo, {C}. and {C}alas, {G}. and {R}aju, {P}. {V}. {S}. and {G}latzel, {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he oxidation state of vanadium in natural and synthetic {F}e-{T}i oxides is determined using high-energy resolution fluorescence-detected {X}-ray absorption spectroscopy ({HERFD}-{XAS}). {E}leven natural magnetite-bearing samples from a borehole of the {M}ain {M}agnetite {L}ayer of the {B}ushveld {C}omplex ({S}outh {A}frica), five synthetic {F}e oxide samples, and three natural hematite-bearing samples from {D}harwar supergroup ({I}ndia) are investigated. {V} {K} edge spectra were recorded on the {ID}26 beamline at the {E}uropean {S}ynchrotron {R}adiation {F}acility ({G}renoble, {F}rance), and the pre-edge features were used to determine the local environment and oxidation state of vanadium. {I}n the case of the magnetite samples (natural and synthetic), we show that vanadium is incorporated in the octahedral site of the spinel structure under two oxidation states: +{III} and +{IV}. {T}he variations of the pre-edge area are interpreted as various proportions in {V}3+ and {V}4+ (between 9.5 and 16.3% of {V}4+), {V}3+ being the main oxidation state. {I}n particular, the variations of the {V}4+/{V}3+ ratio along the profile of the {M}ain {M}agnetite {L}ayer seem to follow the crystallization sequence of the layer. {I}n the case of the hematite samples from {I}ndia, the pre-edge features indicate that vanadium is substituted to {F}e and mainly incorporated as {V}4+ (between 40 and 72% of {V}4+). {W}e also demonstrate the potentiality of {HERFD}-{XAS} for mineralogical studies, since it can filter out the unwanted fluorescence and give better resolved spectra than conventional {XAS}.},
  keywords = {{V}anadium ; {I}mpurity ; {O}xidation state ; {V} {K} edge {HERFD}-{XAS} ; {F}e-{T}i oxides},
  booktitle = {},
  journal = {{P}hysics and {C}hemistry of {M}inerals},
  volume = {38},
  numero = {6},
  pages = {449--458},
  ISSN = {0342-1791},
  year = {2011},
  DOI = {10.1007/s00269-011-0418-3},
  URL = {https://www.documentation.ird.fr/hor/fdi:010053495},
}