Cation site occupancy of biogenic magnetite compared to polygenic ferrite spinels determined by X-ray magnetic circular dichroism

Victoria S. Coker, Carolyn I. Pearce, Claus Lang, Laan Gerrit Van Der, Richard A D Pattrick, Neil D. Telling, Dirk Schüler, Elke Arenholz, Jonathan R. Lloyd

Research output: Contribution to journalArticlepeer-review

Abstract

Ferrite spinels, especially magnetite (Fe3O4), can be formed either by geological, biological or chemical processes leading to chemically similar phases that show different physical characteristics. We compare, for the first time, magnetite produced by these three different methods using X-ray magnetic circular dichroism (XMCD), a synchrotron radiation based technique able to determine the site occupancy of Fe cations in the ferrite spinels. Extracellular nanoscale magnetite produced by different Fe(III)- reducing bacteria was shown to have different degrees of stoichiometry depending on the bacteria and the method of formation, but all were oxygen deficient due to formation under anoxic conditions. Intracellular nano-magnetite synthesized in the magnetosomes of magnetotactic bacteria was found to have a Fe cation site occupancy ratio most similar to stoichiometric magnetite, possibly due to the tight physiological controls exerted by the magnetosome membrane. Chemically-synthesised nano-magnetite and bulk magnetite produced as a result of geological processes were both found to be cation deficient with a composition between magnetite and maghemite (oxidised magnetite). © 2007 E. Schweizerbart'sche Verlagsbuchhandlung.
Original languageEnglish
Pages (from-to)707-716
Number of pages9
JournalEuropean Journal of Mineralogy
Volume19
Issue number5
DOIs
Publication statusPublished - Sept 2007

Keywords

  • Biogenic magnetite
  • Biominer-alogy
  • Fe(III) reduction
  • Geobacter
  • Metal reduction
  • Nanoparticles
  • X-ray magnetic circular dichroism
  • XMCD

Research Beacons, Institutes and Platforms

  • Dalton Nuclear Institute

Fingerprint

Dive into the research topics of 'Cation site occupancy of biogenic magnetite compared to polygenic ferrite spinels determined by X-ray magnetic circular dichroism'. Together they form a unique fingerprint.

Cite this