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
Option D) In hcp (hexagonal close packing), the third layer is placed over the second layer in such a way that the spheres cover the tetrahedral voids, a 3−D close packing is obtained where the layers of the spheres are in alternate patterns (i.e., the third layer is directly over the first layer and the fourth layer is over the second layer). Calling the first layer A and the second layer B, the arrangement is ABAB pattern of hexagonal close packing(hcp).
