An allotropic form of the element @[email protected] with cubic structure (space group \(O_{h}^{7}- Fd3m\)) which is thermodynamically @[email protected] at pressures above \(6\ \text{GPa}\) at room temperature and @[email protected] at atmospheric pressure. At low pressures diamond converts rapidly to @[email protected] at temperatures above \(1900\ \text{K}\) in an @[email protected] atmosphere. The chemical bonding between the carbon atoms is covalent with \(\mathrm{sp}^{3}\) @[email protected]
There is also a hexagonal diamond-like structure of the element carbon (lonsdaleite).
PAC, 1995, 67, 473. (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 487 [Terms] [Paper]