Which of the following is not true about the voids formed in 3 dimensional hexagonal close packed structure?

Options

A. A tetradehral void is formed when a sphere of the second layer is present above triangular void in the first layer
B. All the triangular voids are not covered by the spheres of the second layer
C. Tetrahedral voids are formed when the triangular voids in the second layer lie above the triangular voids in the first layer and the triangular voids in the first and the triangular shapes of these voids do not overlap
D. Octahedral voids are foremd when the triangular voids in the second layer exactly overlap with similar voids in the first layer.

Answer

C,D

Explanation

Tetrahedral voids are formed when the triangular void in the second layer lie exactly above the triangular voids in the first layer and the triangular shape of these voids oppositely overlap.