Altered chemistry of oxygen and iron under deep Earth conditions
Altered chemistry of oxygen and iron under deep Earth conditions
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DOI：
10.1038/s41467-018-08071-3
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发表时间：
2019-01-11
影响因子：
16.6
通讯作者：
Mao, Wendy L.
中科院分区：
文献类型：
--
作者：
Liu, Jin;Hu, Qingyang;Mao, Wendy L.
最近在地球深部条件下的Fe-O-H系统中发现了一种急剧变化的化学反应，涉及铁超氧化物（FeO（2）Hx，x = 0至1）的形成，但该系统在高压下令人困惑的晶体化学基本上是未知的。在这里，我们提出的证据表明，尽管在FeO（2）Hx的高O/Fe比，铁保持在亚铁，自旋配对和非磁性状态在60-133 GPa，而氢的存在对铁的价态的影响很小。由于氧-氧相互作用，还原的铁伴随有氧化的氧。氧的价态不像其他主要地幔矿物那样为-2，而是在-1左右变化。这一结果表明，像铁一样，氧气在我们星球的内部可能有多个价态。我们的研究表明，在地球深部条件下，氧、铁和氢的化学行为可能会发生变化。
A drastically altered chemistry was recently discovered in the Fe-O-H system under deep Earth conditions, involving the formation of iron superoxide (FeO(2)Hx with x = 0 to 1), but the puzzling crystal chemistry of this system at high pressures is largely unknown. Here we present evidence that despite the high O/Fe ratio in FeO(2)Hx, iron remains in the ferrous, spin-paired and non-magnetic state at 60-133 GPa, while the presence of hydrogen has minimal effects on the valence of iron. The reduced iron is accompanied by oxidized oxygen due to oxygen-oxygen interactions. The valence of oxygen is not -2 as in all other major mantle minerals, instead it varies around -1. This result indicates that like iron, oxygen may have multiple valence states in our planet's interior. Our study suggests a possible change in the chemical paradigm of how oxygen, iron, and hydrogen behave under deep Earth conditions.