Practicing Success
How many total numbers of voids are present in a CCP lattice? |
4 8 12 16 |
12 |
The correct answer is option 3. 12. In a cubic close packing (CCP) lattice, also known as a face-centered cubic (FCC) lattice, there are two types of voids present: octahedral voids and tetrahedral voids. Octahedral Voids: Each octahedral void is surrounded by 6 close-packed spheres (atoms). In a CCP lattice, there is one octahedral void centered at the body center of each unit cell. Since there is one octahedral void per close-packed atom, the number of octahedral voids in a CCP lattice is equal to the number of close-packed atoms, which is 4 per unit cell. Therefore, the total number of octahedral voids in a CCP lattice is \(4 \times 1 = 4\). Tetrahedral Voids: Each tetrahedral void is surrounded by 4 close-packed spheres (atoms). In a CCP lattice, there are two tetrahedral voids associated with each close-packed atom. Since there are 4 close-packed atoms per unit cell, there are \(4 \times 2 = 8\) tetrahedral voids per unit cell. Total Number of Voids: Octahedral Voids: 4 Tetrahedral Voids: 8 So, the total number of voids in a CCP lattice is \(4 + 8 = 12\). |