Basic Definition
Boron Nitride (BN):
- Boron Nitride (BN) is a chemical compound composed of boron (B) and nitrogen (N) with a 1:1 ratio. It exists in multiple crystalline forms, including hexagonal, cubic, and wurtzite structures.
- Essentially, Boron Nitride (BN) is the umbrella term for all forms of boron nitride.
Hexagonal Boron Nitride (h-BN):
- Hexagonal Boron Nitride (h-BN) is a specific crystalline form of BN. Its structure is similar to graphite: layers of hexagonal lattices stacked on top of each other. It is sometimes called “white graphite” because of this similarity.
Crystal Structure
| Feature | Boron Nitride (BN) (general) | Hexagonal Boron Nitride (h-BN) |
| Crystal form | Multiple: cubic (c-BN), hexagonal (h-BN), wurtzite (w-BN) | Hexagonal lattice |
| Layered structure | Only h-BN has layered structure | Yes, layers can slide like graphite |
| Bonding | Covalent in all forms, with varying degrees of polarity | Strong in-plane covalent bonds, weak interlayer van der Waals forces |
Physical Properties
Boron Nitride (general):
- Color: White or colorless
- Hardness: Depends on form (c-BN is extremely hard, 2nd to diamond; h-BN is soft and lubricating)
- Thermal conductivity: High, varies by type
- Electrical conductivity: Insulator (except some modified forms)
Hexagonal Boron Nitride specifically:
- Soft, lubricating, slippery
- High thermal stability (up to ~1000°C in air)
- Excellent electrical insulator
- Chemically inert
Uses
Boron Nitride (general):
- c-BN: Cutting tools, abrasives
- w-BN: Research applications, extreme high-pressure tools
- h-BN: Lubricants, cosmetics, thermal management
Hexagonal Boron Nitride (h-BN) specifically:
- Solid lubricant at high temperatures
- Coatings for oxidation resistance
- Thermal conductive fillers in electronics
- Cosmetic powders and skincare
Key Differences
| Aspect | Boron Nitride (BN) | Hexagonal Boron Nitride (h-BN) |
| Scope | General compound | Specific form of BN |
| Hardness | Varies by form | Soft and lubricating |
| Structure | Can be cubic, hexagonal, wurtzite | Hexagonal only |
| Applications | Broad, depends on form | Lubrication, thermal management, cosmetics |