Ambient-Pressure Polymerization of Carbon Anions in the High-Pressure Phase Mg2C

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• 作者：Stevce Stefanoski ; Hanyu Liu ; Yansun Yao ; Timothy A. Strobel
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：November 16, 2015
• 年：2015
• 卷：54
• 期：22
• 页码：10761-10765
• 全文大小：356K
• ISSN：1520-510X

文摘

Experimental and theoretical methods were employed to investigate the ambient-pressure, metastable phase transition pathways for Mg₂C, which was recovered after high-pressure synthesis. We demonstrate that at temperatures above 600 K isolated C^{4鈥?/sup> anions within the Mg₂C structure polymerize into longer-chain carbon polyanions, resulting in the formation of the 伪-Mg₂C₃ (Pnnm) structure, which is another local energy minimum for the carbon鈥搈agnesium system. Access to the thermodynamic ground state (decomposition into graphite) was achieved at temperatures above 鈭?000 K. These results indicate that recoverable high-pressure materials can serve as useful high-energy precursors for ambient-pressure materials synthesis, and they show a novel mechanism for the formation of carbon chains from methanide structures.}