@article{PAR00015684,
  title = {{E}ffect of iron and trivalent cations on {OH} defects in olivine},
  author = {{B}lanchard, {M}. and {I}ngrin, {J}. and {B}alan, {E}tienne and {K}ovacs, {I}. and {W}ithers, {A}. {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{H}ydrogen incorporation in olivine involves many {OH} defects, which will control the hydrogen solubility at mantle conditions. {S}everal of these {OH} defects are identified from the investigation of forsterite (the olivine {M}g end-member). {W}e study here the effect of {F}e2+, {F}e3+, {A}l3+, and {C}r3+ on {OH} defects to improve our understanding of the hydrogen speciation in natural olivine. {L}ow-temperature infrared spectra (-194 degrees {C}) are collected on synthetic and natural olivines. {T}hese spectra are then interpreted in the light of the theoretical determination of the structural, vibrational, and infrared spectroscopic properties of {F}e-related {OH} defects, using first-principles calculations based on density functional theory. {T}he presence of {F}e2+ changes the cationic environment around the fully protonated vacancies in forsterite, leading to a slight modification of their infrared signatures. {I}n particular, the presence of {F}e2+ in an octahedral site adjacent to a hydrogarnet-type defect is likely responsible for the additional bands observed at 3599 cm(-1) and around 3520-3550 cm(-1) in {F}e-doped olivines. {R}esults show that the {OH} bands between 3310 and 3380 cm(-1) are associated with the presence of trivalent cations. {S}pecifically, two bands at 3323 and 3358 cm(-1), commonly observed in natural olivine, are associated with the substitution of {M}g2+ by {C}r3+ while two similar bands at 3328 and 3353 cm-' are associated with the substitution of {M}g2+ by {F}e3+. {T}he presence of these defects and the "titanoclinohumite" defect in natural olivine clearly underlines the prominent role of trace elements on the hydrogen incorporation in lithospheric olivine.},
  keywords = {{O}livine ; {OH} defect ; iron ; chromium ; aluminum ; {IR} spectroscopy ; ab initio ; calculations ; {DFT}},
  booktitle = {},
  journal = {{A}merican {M}ineralogist},
  volume = {102},
  numero = {1-2},
  pages = {302--311},
  ISSN = {0003-004{X}},
  year = {2017},
  DOI = {10.2138/am-2017-5777},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00015684},
}