sir explain why tetrahedral voids are twice than octahedral voids?
If one layer of spheres is kept on a second layer in a cubic closed packed arrangement, then the arrangement is as shown in figure 1 (for tetrahedral hole) giving an arrangement that is twice as shown in figure 2 (for octahedral hole). Therefore, the tetrahedral holes are in double number than the octahedral holes.
If octahedral voids are ‘n’, then the tetrahedral voids are ‘2n’.
Figure 1 Figure 2