Dataset Information

Structural transition and re-emergence of iron's total electron spin in (Mg,Fe)O at ultrahigh pressure.

ABSTRACT: Fe-bearing MgO [(Mg_1-xFe_x)O] is considered a major constituent of terrestrial exoplanets. Crystallizing in the B1 structure in the Earth's lower mantle, (Mg_1-xFe_x)O undergoes a high-spin (S = 2) to low-spin (S = 0) transition at ∼45 GPa, accompanied by anomalous changes of this mineral's physical properties, while the intermediate-spin (S = 1) state has not been observed. In this work, we investigate (Mg_1-xFe_x)O (x ≤ 0.25) up to 1.8 TPa via first-principles calculations. Our calculations indicate that (Mg_1-xFe_x)O undergoes a simultaneous structural and spin transition at ∼0.6 TPa, from the B1 phase low-spin state to the B2 phase intermediate-spin state, with Fe's total electron spin S re-emerging from 0 to 1 at ultrahigh pressure. Upon further compression, an intermediate-to-low spin transition occurs in the B2 phase. Depending on the Fe concentration (x), metal-insulator transition and rhombohedral distortions can also occur in the B2 phase. These results suggest that Fe and spin transition may affect planetary interiors over a vast pressure range.

SUBMITTER: Hsu H

PROVIDER: S-EPMC9120148 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Structural transition and re-emergence of iron's total electron spin in (Mg,Fe)O at ultrahigh pressure.

Hsu Han H Umemoto Koichiro K

Nature communications 20220519 1

Fe-bearing MgO [(Mg1-xFex)O] is considered a major constituent of terrestrial exoplanets. Crystallizing in the B1 structure in the Earth's lower mantle, (Mg1-xFex)O undergoes a high-spin (S = 2) to low-spin (S = 0) transition at ∼45 GPa, accompanied by anomalous changes of this mineral's physical properties, while the intermediate-spin (S = 1) state has not been observed. In this work, we investigate (Mg1-xFex)O (x ≤ 0.25) up to 1 ...[more]

PMID: 35589702

Similar Datasets

Project description:Whole-genome DNA microarray analysis of Geobacter sulfurreducens cells grown on Fe(III)-oxide or Mn(IV)-oxide versus cells grown on soluble Fe(III) citrate indicated that there were significant differences in transcription patterns during growth on the insoluble metal oxides compared to growth on soluble Fe(III). Many of the genes that appeared to be up-regulated during growth on the metal hydroxides were involved in electron transport. The most highly up-regulated genes for both conditions were omcS and omcT, which encode co-transcribed c-type cytochromes exposed on the outer surface of the cell that are known to be required for Fe(III) and Mn(IV)-oxide reduction. Other electron transport genes that were up-regulated on both insoluble metals included the gene coding for the outer membrane c-type cytochrome, OmcG, genes for the outer membrane proteins, OmpB and OmpC, and the gene that codes for the structural protein of electrically conductive pili, PilA. Genes that were up-regulated in cells grown on Fe(III)-oxide but not Mn(IV)-oxide, included outer membrane c-type cytochromes including OmcE, a putative DMSO reductase protein, and proteins from the cytochrome bc1 complex. Electron transport genes that were only up-regulated in Mn(IV)-oxide grown cells included the genes that code for the outer membrane c-type cytochromes, OmcZ and OmcB, the periplasmic c-type cytochrome, MacA, and fumarate reductase. Genetic studies indicated that the c-type cytochrome proteins, PpcH, OmcJ, OmcM, OmcV, MacA, OmcF, OmcI, and OmcQ, and the iron sulfur subunit of the cytochrome b/b6 complex, QcrA, are important for reduction of insoluble Fe(III)-oxides but do not appear to be important for Mn(IV) reduction. These results demonstrate that the physiology of Fe(III) reducing bacteria differ significantly during growth on insoluble electron and soluble electron acceptors and emphasizes the importance of c-type cytochromes in extracellular electron transfer in G. sulfurreducens. Geobacter sulfurreducens cells were grown with acetate (5 mM) provided as the electron donor and either Fe(III) oxide or Fe(III) citrate provided as the electron acceptor. Cells were harvested at mid-log and total RNA was extracted. Total RNA (0.5 μg) was amplified using the MessageAmp II-Bacteria Kit (Ambion, Foster City, CA) according to the manufacturers instructions. Ten micrograms of amplified RNA (aRNA) was chemically labeled with Cy3 (for the control or soluble electron acceptor condition) or Cy5 (for the experimental or insoluble electron acceptor condition) dye using the MicroMax ASAP RNA Labeling Kit (Perkin Elmer, Wellesley, MA) according to the manufacturer’s instructions.

Dataset Information

Structural transition and re-emergence of iron's total electron spin in (Mg,Fe)O at ultrahigh pressure.

Publications

Structural transition and re-emergence of iron's total electron spin in (Mg,Fe)O at ultrahigh pressure.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets