Confirmation of the assignment of vibrations of goethite: an ATR and IES study of goethite structure.
Transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM/EDS) and X-ray diffraction (XRD) were used to characterize the morphology of synthetic goethite. The behavior of the hydroxyl/water molecular units of goethite and its thermally treated products were characterized using Fourier transform-infrared emission spectroscopy (FT-IES) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The results showed that all the expected vibrational bands between 4000 and 650 cm(-1) including the resolved bands (3800-2200 cm(-1)) were confirmed. A band attributed to a new type of hydroxyl unit was found at 3708 cm(-1) and assigned to the FeO-H stretching vibration without hydrogen bonding. This hydroxyl unit was retained up to the thermal treatment temperature of 500 °C. On the whole, seven kinds of hydroxyl units, involving three surface hydroxyls, a bulk hydroxyl, a FeO-H without hydrogen bonding, a nonstoichiometric hydroxyl and a reversed hydroxyl were observed, and three kinds of adsorbed water were found in/on goethite.
School of Resources & Environmental Engineering, Hefei University of Technology, China; School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Australia.
Haibo
H
Liu
Tianhu
T
Chen
Chengsong
C
Qing
Qiaoqin
Q
Xie
Ray L
RL
Frost
D006860:Hydrogen Bonding; D017665:Hydroxyl Radical / Q000737:chemistry; D058085:Iron Compounds / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D014867:Water / Q000737:chemistry
D058085:Iron Compounds; D008903:Minerals; D014867:Water; C094886:goethite; D017665:Hydroxyl Radical
Goethite structure; Hydrogen bonding; Hydroxyl; Infrared spectroscopy; Surface hydroxyls