IMA 2019-019 = hiroseite

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Marco E. Ciriotti
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IMA 2019-019 = hiroseite

Messaggio da Marco E. Ciriotti » mar 14 gen, 2020 11:45

▪ Bindi, L., Shim, S.H., Sharp, T.G., Xie, X. (2020): Evidence for the charge disproportionation of iron in extraterrestrial bridgmanite. Science Advances, 6, eaay7893.

Bridgmanite, MgSiO3 with perovskite structure, is considered the most abundant mineral on Earth. On the lower mantle, it contains Fe and Al that strongly influence its behavior. Experimentalists have debated whether iron may exist in a mixed valence state, coexistence of Fe2+ and Fe3+ in bridgmanite, through charge disproportionation. Here, we report the discovery of Fe-rich aluminous bridgmanite coexisting with metallic iron in a shock vein of the Suizhou meteorite. This is the first direct evidence in nature of the Fe disproportionation reaction, which so far has only been observed in some high-pressure experiments. Furthermore, our discovery supports the idea that the disproportionation reaction would have played a key role in redox processes and the evolution of Earth.
Marco E. Ciriotti

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Re: IMA 2019-019 = hiroseite

Messaggio da TOSATO FABIO » mar 14 gen, 2020 23:50

Tosato Fabio
"Il vero viaggio di scoperta non consiste nel cercare nuove terre, ma nell'avere nuovi occhi." M. Proust
Noi siamo anche quello che non siamo riusciti ad essere.
Sic transit gloria mundi.


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