Diamond
C
Description
Diamond is a solid form of the element carbon with its atoms arranged in a unique crystal structure called diamond cubic. While graphite is the more stable form of carbon at room temperature, the transition from diamond to graphite is so slow that it is practically non-existent. Diamond is globally recognized for possessing the highest hardness and thermal conductivity of any naturally occurring material.
Crystallographic Structure
For material scientists and developers building 3D visualizations, the diamond structure is a fascinating modification of the cubic system. It consists of two interpenetrating Face-Centered Cubic (FCC) lattices, where one is shifted relative to the other by a vector of $(1/4, 1/4, 1/4)$ along the body diagonal.
- Crystal System: Cubic (Diamond Cubic)
- Lattice Parameter: $a = 3.567$ Å.
- Bonding: Each carbon atom undergoes $sp^3$ hybridization, forming four strong covalent bonds.
- Coordination Number: 4 (Tetrahedral geometry).
- Atomic Packing Factor (APF): 0.34. Unlike the FCC structure in metals (0.74), the diamond structure is relatively "open" due to the fixed bond angles of the $sp^3$ orbitals.
Properties
Atomic & Physical Properties
The extraordinary properties of diamond arise from the strength and directionality of the covalent bonds between its carbon atoms.
- Atomic Number: 6 (Carbon)
- Atomic Mass: 12.011 u
- Melting Point: ~4,027°C (under extreme pressure)
- Hardness: 10 on the Mohs scale (the highest)
- Thermal Conductivity: 900–2,320 W/m·K (roughly 5x higher than copper)
- Refractive Index: 2.417 (extremely high, contributing to its brilliance)
Applications
- Industrial Abrasives: Diamond-tipped saws, drill bits, and polishing powders for working with hard materials like stone or specialized alloys.
- Optics: Used in high-pressure windows for vacuum chambers and specialized lenses for high-power CO2 lasers.
- Quantum Computing: Research into Nitrogen-Vacancy (NV) centers in diamond is a leading frontier for creating stable quantum bits (qubits) at room temperature.
- Jewelry: Leverages its high refractive index and dispersion to create the characteristic "fire" and brilliance found in gemstones.
Unit Cell Axes
a=3.57 b=3.57 c=3.57
Unit Cell Angles
α=90° β=90° γ=90°
Lattice Type
fcc
Grid Expansion
Appearance
Coordination