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Title: Pressure induced polymerization of acetylide anions in CaC 2 and 10 7 fold enhancement of electrical conductivity

Abstract

Transformation between different types of carbon–carbon bonding in carbides often results in a dramatic change of physical and chemical properties. Under external pressure, unsaturated carbon atoms form new covalent bonds regardless of the electrostatic repulsion. It was predicted that calcium acetylide (also known as calcium carbide, CaC2) polymerizes to form calcium polyacetylide, calcium polyacenide and calcium graphenide under high pressure. In this work, the phase transitions of CaC2 under external pressure were systematically investigated, and the amorphous phase was studied in detail for the first time. Polycarbide anions like C 6 6- are identified with gas chromatography-mass spectrometry and several other techniques, which evidences the pressure induced polymerization of the acetylide anions and suggests the existence of the polyacenide fragment. Additionally, the process of polymerization is accompanied with a 107 fold enhancement of the electrical conductivity. The polymerization of acetylide anions demonstrates that high pressure compression is a viable route to synthesize novel metal polycarbides and materials with extended carbon networks, while shedding light on the synthesis of more complicated metal organics.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1338999
Resource Type:
Journal Article
Journal Name:
Chemical Science
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2041-6520
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Zheng, Haiyan, Wang, Lijuan, Li, Kuo, Yang, Youyou, Wang, Yajie, Wu, Jiajia, Dong, Xiao, Wang, Chun-Hai, Tulk, Christopher A., Molaison, Jamie J., Ivanov, Ilia N., Feygenson, Mikhail, Yang, Wenge, Guthrie, Malcolm, Zhao, Yusheng, Mao, Ho-Kwang, and Jin, Changqing. Pressure induced polymerization of acetylide anions in CaC 2 and 10 7 fold enhancement of electrical conductivity. United States: N. p., 2016. Web. doi:10.1039/C6SC02830F.
Zheng, Haiyan, Wang, Lijuan, Li, Kuo, Yang, Youyou, Wang, Yajie, Wu, Jiajia, Dong, Xiao, Wang, Chun-Hai, Tulk, Christopher A., Molaison, Jamie J., Ivanov, Ilia N., Feygenson, Mikhail, Yang, Wenge, Guthrie, Malcolm, Zhao, Yusheng, Mao, Ho-Kwang, & Jin, Changqing. Pressure induced polymerization of acetylide anions in CaC 2 and 10 7 fold enhancement of electrical conductivity. United States. doi:10.1039/C6SC02830F.
Zheng, Haiyan, Wang, Lijuan, Li, Kuo, Yang, Youyou, Wang, Yajie, Wu, Jiajia, Dong, Xiao, Wang, Chun-Hai, Tulk, Christopher A., Molaison, Jamie J., Ivanov, Ilia N., Feygenson, Mikhail, Yang, Wenge, Guthrie, Malcolm, Zhao, Yusheng, Mao, Ho-Kwang, and Jin, Changqing. Wed . "Pressure induced polymerization of acetylide anions in CaC 2 and 10 7 fold enhancement of electrical conductivity". United States. doi:10.1039/C6SC02830F.
@article{osti_1338999,
title = {Pressure induced polymerization of acetylide anions in CaC 2 and 10 7 fold enhancement of electrical conductivity},
author = {Zheng, Haiyan and Wang, Lijuan and Li, Kuo and Yang, Youyou and Wang, Yajie and Wu, Jiajia and Dong, Xiao and Wang, Chun-Hai and Tulk, Christopher A. and Molaison, Jamie J. and Ivanov, Ilia N. and Feygenson, Mikhail and Yang, Wenge and Guthrie, Malcolm and Zhao, Yusheng and Mao, Ho-Kwang and Jin, Changqing},
abstractNote = {Transformation between different types of carbon–carbon bonding in carbides often results in a dramatic change of physical and chemical properties. Under external pressure, unsaturated carbon atoms form new covalent bonds regardless of the electrostatic repulsion. It was predicted that calcium acetylide (also known as calcium carbide, CaC2) polymerizes to form calcium polyacetylide, calcium polyacenide and calcium graphenide under high pressure. In this work, the phase transitions of CaC2 under external pressure were systematically investigated, and the amorphous phase was studied in detail for the first time. Polycarbide anions like C66- are identified with gas chromatography-mass spectrometry and several other techniques, which evidences the pressure induced polymerization of the acetylide anions and suggests the existence of the polyacenide fragment. Additionally, the process of polymerization is accompanied with a 107 fold enhancement of the electrical conductivity. The polymerization of acetylide anions demonstrates that high pressure compression is a viable route to synthesize novel metal polycarbides and materials with extended carbon networks, while shedding light on the synthesis of more complicated metal organics.},
doi = {10.1039/C6SC02830F},
journal = {Chemical Science},
issn = {2041-6520},
number = 1,
volume = 8,
place = {United States},
year = {2016},
month = {8}
}