Carbon can exist in many different forms at different temperatures and pressures. Some allotropes of carbon have been predicted in theory but still have not been found in nature. In this article, we mainly overview a number of three-dimensional (3D) crystalline carbon allotropes, predicted by ab initio calculations. Particular attention will be placed on the carbon foams, which possess porous structures with a large surface area. Carbon foams are mostly composed of graphite segments connected by different types of carbon bonds. We will also review 3D carbon superstructures of low-dimensional allotropes, typically built from carbon fullerenes, nanobuds, nanotubes and graphene nanoribbons, as well as various other 3D crystalline carbon structures. Some of these carbon superstructures are composed of mixed sp-sp 2 carbon or pure sp 2 carbon (e.g., H-6, bct-4, C-20, K 4), and some have larger mass density than diamond (C 8, hP3, tl12, tp12), and some can be transformed from graphite at room temperature and high pressure (e.g., M carbon, bct-4 carbon, W carbon, Z carbon). Some of these theoretically predicted carbon allotropes may be synthesized in the laboratory in future.
|Original language||English (US)|
|Number of pages||8|
|Journal||Progress in Chemistry|
|State||Published - Jun 2012|
- 3D crystalline carbon allotropes
- Carbon foams
ASJC Scopus subject areas