Ncert Exercises & Solutions

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

I.	A tetrahedral void is formed when a sphere of the second layer is present above the triangular void in the first layer
II.	All the triangular voids are not covered by the spheres of the second layer
III.	Tetrahedral voids are formed when the triangular voids in the second layer lie above the triangular voids in the first layer and the triangular shapes of these voids do not overlap
IV.	Octahedral voids are formed when the triangular voids in the second layer exactly overlap with similar voids in the first layer

The correct choice among the given is -

1. (I, II)

2. (II, III)

3. (III, IV)

4. (I, III)