Question

The number of tetrahedral voids present on each body diagonal in CCP unit cell is:

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

Answer: (B)

2

In ccp, number of atoms present per unit cell $=4$

Since in cubic closed packing, the number of tetrahedral voids is equal to twice the number of atoms present per unit cell, hence

Number of tetrahedral voids$=2\times 4=8$

These $\ast$ voids are uniformly distributed over each of the $4$ body diagonals. Therefore,

Number of tetrahedral voids present on each body diagonal in CCP unit cell $=\frac{8}{4}=2$