Which of the following statement is not true about the hexagonal close packing?
Which of the following statement is not true about the hexagonal close packing?

(i) The coordination number is 12.

(ii) It has 74% packing efficiency.

(iii) Tetrahedral voids of the second layer are covered by the spheres of the third layer.

(iv) In this arrangement spheres of the fourth layer are exactly aligned with those of the first layer.

 

 

Correct Answer: (iv) In this arrangement spheres of the fourth layer are exactly aligned with those of the first layer.

Explanation: Closed Hexagonal packaging can be arranged in two layers A and B respectively which can be represented by a degree.

Here, we can easily see that the first layer and the 4th alignment are not exactly aligned.

The coordination number of the atom in hcp i= 12

Packaging fraction of hcp = 74%.

The Tetrahedral void of the second layer is covered by spheres of the third layer.