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

Options

A. A tetrahedral 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 shapes of these voids do not overlap
D. Octahedral voids are formed when the triangular voids in the second layer exactly overlap with similar voids in the first layer.

Answer

c,d

Explanation

(c ) is not true because octahedral voids are formed when triangular voids in the second layer lie above the triangular voids of the first layer .
(d) is not true because octahedral void is combination of two triangular voids one with vertex upward and the other with vertex downward and not their overlap