Dense Carbon Monoxide to 160 GPa: Stepwise Polymerization to Two-Dimensional Layered Solid

• Published in: Journal of physical chemistry. C Vol. 120; no. 48; pp. 27548 - 27554
• Main Authors: Ryu, Young-Jay, Kim, Minseob, Lim, Jinhyuk, Dias, Ranga, Klug, Dennis, Yoo, Choong-Shik
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 08.12.2016
• Subjects: band structure; chemical structure; inorganic carbon compounds; MATERIALS SCIENCE; oxides; phase transitions
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.6b09434

Carbon monoxide (CO) is the first molecular system found to transform into a nonmolecular “polymeric” solid above 5.5 GPa, yet been studied beyond 10 GPa. Here, we show a series of pressure-induced phase transformations in CO to 160 GPa: from a molecular solid to a highly colored, low-density polymeric phase I to translucent, high-density phase II to transparent, layered phase III. The properties of these phases are consistent with those expected from recently predicted 1D P21/m, 3D I212121, and 2D Cmcm structures, respectively. Thus, the present results advocate a stepwise polymerization of CO triple bonds to ultimately a 2D singly bonded layer structure with an enhanced ionic character.