Nano size crystals of goethite, {alpha}-FeOOH: Synthesis and thermal transformation

Journal Article · Sun Apr 15 04:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.01.032· OSTI ID:21015793

Christensen, Axel Norlund ^[1]; Bahl, Christian R.H. ^[2]; DiMasi, Elaine ^[3]

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1. Crystal Chemistry, Hojkolvej 7, DK-8210 Arhus V (Denmark)
2. Materials Research Department, Riso National Laboratory, P.O. Box 49, DK-4000 Roskilde (Denmark)
3. National Synchrotron Light Source Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

An aqueous suspension of amorphous iron(III) hydroxide was kept at room temperature (298 K) for 23 years. During this period of time the pH of the liquid phase changed from 4.3 to 2.85, and nano size crystals of goethite, {alpha}-FeOOH crystallised from the amorphous iron(III) hydroxide. Transmission electron microscopy (TEM) investigations, Moessbauer spectra, and powder X-ray diffraction using Co K{alpha} radiation showed that the only iron containing crystalline phase present in the recovered product was {alpha}-FeOOH. The size of these nano particles range from 10 to 100 nm measured by TEM. The thermal decomposition of {alpha}-FeOOH was investigated by time-resolved in situ synchrotron radiation powder X-ray diffraction and the data showed that the sample of {alpha}-FeOOH transformed to {alpha}-Fe{sub 2}O{sub 3} in the temperature range 444-584 K. A quantitative phase analysis shows the increase in scattered X-ray intensity from {alpha}-Fe{sub 2}O{sub 3} to follow the decrease of intensity from {alpha}-FeOOH in agreement with the topotactic phase transition. - Graphical abstract: Nano size crystals of goethite, {alpha}-FeOOH formed from amorphous iron(III) hydroxide after 23 years, and transforms faster to {alpha}-Fe{sub 2}O{sub 3} upon heating.

• OSTI ID: 21015793
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 4 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
GOETHITE
IRON HYDROXIDES
IRON OXIDES
MOESSBAUER EFFECT
PHASE STUDIES
PHASE TRANSFORMATIONS
SYNCHROTRON RADIATION
SYNTHESIS
TEMPERATURE RANGE 0273-0400 K
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION