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

The correct option is (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 × 4 = 8

These ∗ 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 = 8/4 = 2