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

被引：52

作者：

Coker, Victoria S. ^{[1
,2
]}

Pearce, Carolyn I. ^{[1
,2
]}

Lang, Claus ^{[4
]}

van der Laan, Gerrit ^{[1
,2
,3
]}

Pattrick, Richard A. D. ^{[1
,2
]}

Telling, Neil D. ^{[3
]}

Schueler, Dirk ^{[4
]}

Arenholz, Elke ^{[5
]}

Lloyd, Jonathan R. ^{[1
,2
]}

机构：

[1] Univ Manchester, Sch Earth Atmospher & Environm Sci, Manchester M13 9PL, Lancs, England

[2] Univ Manchester, Williamson Res Ctr Mol Environm Sci, Manchester M13 9PL, Lancs, England

[3] SERC, Daresbury Lab, Magnet Spect Grp, Warrington WA4 4AD, Cheshire, England

[4] Max Planck Inst Marine Microbiol, D-28359 Bremen, Germany

[5] Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA

来源：

EUROPEAN JOURNAL OF MINERALOGY | 2007年 / 19卷 / 05期

基金：

英国自然环境研究理事会; 英国生物技术与生命科学研究理事会; 英国工程与自然科学研究理事会;

关键词：

X-ray magnetic circular dichroism; XMCD; nanoparticles; metal reduction; Fe(III) reduction; Geobacter; biomineralogy; biogenic magnetite;

D O I：

10.1127/0935-1221/2007/0019-1758

中图分类号：

P57 [矿物学];

学科分类号：

070901 ;

摘要：

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(Ill)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).

引用

页码：707 / 716

页数：10

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