Structure of naturally hydrated ferrihydrite revealed through neutron diffraction and first-principles modeling
| Autor: | Jonathan J. Powell, Helen F. Chappell, Nuno Faria, Daniel T. Bowron, William Thom, P. J. Hasnip |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Diffraction
chemistry.chemical_classification Materials science Physics and Astronomy (miscellaneous) Neutron diffraction 02 engineering and technology 010502 geochemistry & geophysics 021001 nanoscience & nanotechnology 01 natural sciences Amorphous solid Characterization (materials science) Coordination complex Ferrihydrite Crystallography chemistry Chemical physics General Materials Science Reactivity (chemistry) Density functional theory 0210 nano-technology 0105 earth and related environmental sciences |
| ISSN: | 2475-9953 |
| Popis: | Ferrihydrite, with a ``two-line'' x-ray diffraction pattern (2L-Fh), is the most amorphous of the iron oxides and is ubiquitous in both terrestrial and aquatic environments. It also plays a central role in the regulation and metabolism of iron in bacteria, algae, higher plants, and animals, including humans. In this study, we present a single-phase model for ferrihydrite that unifies existing analytical data while adhering to fundamental chemical principles. The primary particle is small (20--50 \AA{}) and has a dynamic and variably hydrated surface, which negates long-range order; collectively, these features have hampered complete characterization and frustrated our understanding of the mineral's reactivity and chemical/biochemical function. Near and intermediate range neutron diffraction (NIMROD) and first-principles density functional theory (DFT) were employed in this study to generate and interpret high-resolution data of naturally hydrated, synthetic 2L-Fh at standard temperature. The structural optimization overcomes transgressions of coordination chemistry inherent within previously proposed structures, to produce a robust and unambiguous single-phase model. |
| Databáze: | OpenAIRE |
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