Diamond
Definition and meaning of Diamond in chemistry.
Diamond is a naturally occurring crystalline allotrope of carbon in which each carbon atom forms four strong covalent sigma bonds to neighboring carbon atoms arranged in a repeating tetrahedral (sp3) lattice.
In more detail
This three-dimensional network of identical, uniformly strong C-C covalent bonds extends throughout the entire crystal, giving diamond its extreme hardness (10 on the Mohs scale), high melting point, and low electrical conductivity, since all valence electrons are localized in bonds rather than free to move. Diamond forms naturally under the very high pressure and temperature conditions found deep in Earth's mantle and is brought to the surface by volcanic activity, though synthetic diamonds are now produced industrially by high-pressure-high-temperature (HPHT) and chemical vapor deposition (CVD) methods. Unlike graphite, another carbon allotrope with the same chemical formula, diamond's tetrahedral bonding geometry prevents layers from sliding past one another.
Key facts
| Formula | C (carbon) |
|---|---|
| Field | Inorganic Chemistry |
| Hardness | 10 on the Mohs scale |
| Crystal structure | Face-centered cubic (diamond cubic lattice), sp3 hybridization |
Industrial diamond grit, made of the same carbon lattice as gem-quality diamond, is bonded onto saw blades and drill bits to cut and grind extremely hard materials like concrete and rock.
Frequently asked questions
Why is diamond so hard while graphite, also pure carbon, is soft?
Diamond's carbon atoms are each bonded to four others in a rigid 3D tetrahedral network, while graphite's carbon atoms bond to only three others in flat layers held together by weak forces, allowing the layers to slide.
Can diamond burn?
Yes. Diamond is pure carbon and will burn in oxygen at high temperature (around 700-900 degrees Celsius), producing carbon dioxide, though this requires much higher temperatures than burning ordinary organic materials.