Term: diamond
https://doi.org/10.1351/goldbook.D01671

Definition:
An allotropic form of the element carbon with cubic structure (space group O h 7- F d 3 m) 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).

Related Terms:
1) carbon (http://doi.org/10.1351/goldbook.C00821).
2) graphite (http://doi.org/10.1351/goldbook.G02684).
3) stable (http://doi.org/10.1351/goldbook.S05900).
4) metastable (http://doi.org/10.1351/goldbook.M03872).
5) inert (http://doi.org/10.1351/goldbook.I03026).
6) hybridization (http://doi.org/10.1351/goldbook.H02874).

Source: PAC, 1995, 67, 473. 'Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)' on page 487 (https://doi.org/10.1351/pac199567030473)

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

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