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Title: The structure of ferrihydrite, a nanocrystalline material.

Abstract

Despite the ubiquity of ferrihydrite in natural sediments and its importance as an industrial sorbent, the nanocrystallinity of this iron oxyhydroxide has hampered accurate structure determination by traditional methods that rely on long-range order. We uncovered the atomic arrangement by real-space modeling of the pair distribution function (PDF) derived from direct Fourier transformation of the total x-ray scattering. The PDF for ferrihydrite synthesized with the use of different routes is consistent with a single phase (hexagonal space group P6{sub 3}mc; a = {approx}5.95 angstroms, c = {approx}9.06 angstroms). In its ideal form, this structure contains 20% tetrahedrally and 80% octahedrally coordinated iron and has a basic structural motif closely related to the Baker-Figgis {delta}-Keggin cluster. Real-space fitting indicates structural relaxation with decreasing particle size and also suggests that second-order effects such as internal strain, stacking faults, and particle shape contribute to the PDFs.

Authors:
; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF); DE; CEMS
OSTI Identifier:
920568
Report Number(s):
ANL/XSD/JA-59566
Journal ID: ISSN 0193-4511; SCEHDK; TRN: US200818%%6
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Science; Journal Volume: 316; Journal Issue: 5832 ; 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; IRON HYDROXIDES; CRYSTAL STRUCTURE; NANOSTRUCTURES; DISTRIBUTION FUNCTIONS; FOURIER TRANSFORMATION; STACKING FAULTS

Citation Formats

Michel, F. M., Ehm, L., Antao, S. M., Lee, P. L., Chupas, P. J., Liu, G., Strongin, D. R., Schoonen, M. A., Phillips, B. L., Parise, J. B., CEMS, Stony Brook Univ., and Temple Univ. The structure of ferrihydrite, a nanocrystalline material.. United States: N. p., 2007. Web. doi:10.1126/science.1142525.
Michel, F. M., Ehm, L., Antao, S. M., Lee, P. L., Chupas, P. J., Liu, G., Strongin, D. R., Schoonen, M. A., Phillips, B. L., Parise, J. B., CEMS, Stony Brook Univ., & Temple Univ. The structure of ferrihydrite, a nanocrystalline material.. United States. doi:10.1126/science.1142525.
Michel, F. M., Ehm, L., Antao, S. M., Lee, P. L., Chupas, P. J., Liu, G., Strongin, D. R., Schoonen, M. A., Phillips, B. L., Parise, J. B., CEMS, Stony Brook Univ., and Temple Univ. Mon . "The structure of ferrihydrite, a nanocrystalline material.". United States. doi:10.1126/science.1142525.
@article{osti_920568,
title = {The structure of ferrihydrite, a nanocrystalline material.},
author = {Michel, F. M. and Ehm, L. and Antao, S. M. and Lee, P. L. and Chupas, P. J. and Liu, G. and Strongin, D. R. and Schoonen, M. A. and Phillips, B. L. and Parise, J. B. and CEMS and Stony Brook Univ. and Temple Univ.},
abstractNote = {Despite the ubiquity of ferrihydrite in natural sediments and its importance as an industrial sorbent, the nanocrystallinity of this iron oxyhydroxide has hampered accurate structure determination by traditional methods that rely on long-range order. We uncovered the atomic arrangement by real-space modeling of the pair distribution function (PDF) derived from direct Fourier transformation of the total x-ray scattering. The PDF for ferrihydrite synthesized with the use of different routes is consistent with a single phase (hexagonal space group P6{sub 3}mc; a = {approx}5.95 angstroms, c = {approx}9.06 angstroms). In its ideal form, this structure contains 20% tetrahedrally and 80% octahedrally coordinated iron and has a basic structural motif closely related to the Baker-Figgis {delta}-Keggin cluster. Real-space fitting indicates structural relaxation with decreasing particle size and also suggests that second-order effects such as internal strain, stacking faults, and particle shape contribute to the PDFs.},
doi = {10.1126/science.1142525},
journal = {Science},
number = 5832 ; 2007,
volume = 316,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}