What is the Difference Between BCC and FCC?
🆚 Go to Comparative Table 🆚The main differences between body-centered cubic (BCC) and face-centered cubic (FCC) structures are related to their atomic arrangements, packing efficiency, coordination numbers, and material properties. Here are the key differences:
- Atomic Arrangement: In a BCC structure, spheres (atoms, molecules, or ions) are located in the corners of a cube and one sphere in the center of the cube. In an FCC structure, spheres are located in the corners of a cube and also in the centers of the cubic faces.
- Packing Efficiency: The FCC structure has a higher packing efficiency than the BCC structure, with a packing efficiency of 74%. The packing factor of BCC is 0.68.
- Coordination Number: The coordination number of BCC is 8, while the coordination number of FCC is 12.
- Ductility and Malleability: FCC structures are more ductile and malleable than BCC structures due to their closer atomic packing.
Examples of metals with BCC structure include Lithium (Li), Sodium (Na), Potassium (K), Chromium (Cr), and Barium (Ba). Examples of metals with FCC structure include Aluminum (Al), Copper (Cu), Gold (Au), Lead (Pb), and Nickel (Ni).
Comparative Table: BCC vs FCC
Face-centered cubic (FCC) and body-centered cubic (BCC) are two of the most iconic crystal structures. They have some differences in terms of atomic arrangement, packing, and properties. Here is a table highlighting the differences between FCC and BCC:
| Feature | FCC | BCC |
|---|---|---|
| Number of Atoms per Unit Cell | 4 | 2 |
| Number of Octahedral Interstitial Sites | 4 | 6 |
| Number of Tetrahedral Interstitial Sites | 8 | 12 |
| Atomic Packing Fraction | Higher | Lower |
| Density | More dense | Less dense |
| Stability at High Temperatures | More stable | Less stable |
| Ductility | More ductile | Less ductile |
FCC metals tend to be more dense, more stable at high temperatures, and more ductile than BCC metals due to their packing arrangement and slip systems.