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

Options

A. The coordination numberr is 12
B. It has `74%` packing efficiency
C. Tetrahedral voids of the second layer are covered by the spheres of the third layer
D. In this arrangement spheres of the forth layer are exatly, aligned with those of the first layer.

Answer

D

Explanation

Statement (d) is not true. In hcp close packing, the spheres of the third layer are exactly allinged with those of the first layer are exactly allinged with those of the first layer. This menas that it is ABAB…. Type arrangement and not ABC ABC … type arrangement.