铁碳酸盐的高压合成,Fe2[CO3]3
Lkhamsuren Bayarjargal1, Dominik Spahr1, Elena Bykova1
1Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, 60438 Frankfurt, Germany.
Inorganic chemistry
|October 28, 2024
概括
我们合成了一种新的碳酸铁,Fe2[CO3]3,在高压和高温下稳定,表明它存在于地球下层地幔. 在这些极端条件下,这种铁 (III) 碳酸盐比铁 (II) 碳酸盐更稳定.
科学领域:
- 矿物学和地质化学
- 高压实验科学高压实验科学
- 计算材料科学 计算材料科学
背景情况:
- 铁碳酸盐是了解地球深层内部的关键矿物质.
- 之前的研究表明, siderite (FeCO3) 在下层地幔条件下不稳定.
- 铁碳酸盐在极端压力和温度下的稳定性和结构仍然是积极研究的领域.
研究的目的:
- 为了合成和表征一种新的铁碳酸盐,Fe2[CO3]3.3.
- 在高压和高温下确定Fe2[CO3]3的结构和热力学特性.
- 评估Fe2[CO3]3在地球下层地幔中的潜在稳定性.
主要方法:
- 使用激光加热的钻石天细胞进行高压合成.
- 单晶X射线衍射用于结构确定.
- 密度函数理论 (DFT) 用于几何优化和属性计算.
主要成果:
- 在大约33 GPa和高温下成功合成Fe2[CO3]3.
- 确定了单临床空间组P21/n中的晶体结构,其中包括7倍和8倍协调的Fe3+.
- 计算出138~34 GPa 的散体模量 (K0).
- 确定了Fe2[CO3]3在~33 GPa时的稳定场,高达2600(300) K.
结论:
- Fe2[CO3]3 是一个稳定的铁碳酸盐阶段在下层地幔条件下.
- 在下层地幔中存在的铁 (III) 碳酸盐比铁 (II) 碳酸盐更有可能存在.
- 这一发现对地球深层碳循环的组成和演变具有重大意义.
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