In this study, we propose a revised structural model for highly ordered synthetic Ge-akaganéite, a stable analogue of tunnel-type Fe-oxyhydroxide, based on the Rietveld refinement of synchrotron X-ray diffraction data and density functional theory with dispersion correction (DFT-D) calculations. In the proposed crystal structure of Ge-akaganéite, Ge is found not only in the tunnel sites as GeO(OH)3 − tetrahedra, but also 4/5 of total Ge atoms are in the octahedral sites substituting 1/10 of Fe. In addition, the tunnel structures are stabilized by the presence of hydrogen bonds between the framework OH and Cl− species, forming a twisted cube structure and the GeO(OH)3 − tetrahedra corner oxygen, forming a conjugation bond. The chemical formula of the synthetic Ge-akaganéite was determined to be (Fe7.2Ge0.8)O8.8(OH)7.2Cl0.8(Ge(OH)4)0.2.
Bibliographical noteFunding Information:
Funding: This research was funded by Research Foundation of Korea, grant number NRF 2018R1D1A1B07051418.
This research was funded by Research Foundation of Korea, grant number NRF 2018R1D1A1B07051418.
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All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Science(all)
- Condensed Matter Physics
- Inorganic Chemistry