diamond

https://doi.org/10.1351/goldbook.D01671
An allotropic form of the element carbon with cubic structure (space group Oh7−Fd3m) which is thermodynamically stable at pressures above 6 GPa at room temperature and metastable at atmospheric pressure. At low pressures diamond converts rapidly to graphite at temperatures above 1900 K in an inert atmosphere. The chemical bonding between the carbon atoms is covalent with sp3 hybridization.
Note: There is also a hexagonal diamond-like structure of the element carbon (lonsdaleite).
Source:
PAC, 1995, 67, 473. (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 487 [Terms] [Paper]
Citation: 'diamond' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.D01671 RIS BibTex EndNote
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