1 mole of hexagonal packed structure contains 1 mole of octahedral voids and two of tetrahedral voids, 0.5 of hexagonal packed structure contains 0.5 ***** of octahedral voids and 1 mole of tetrahedral voids,
No. of tetrahedral voids = 6.022 x 1023
No. of octahedral voids = x No. of tetrahedral voids
No. of octahedral voids = x 6.022 x 1023
= 3.011 x 1023
Total no. of voids = (6.022+3.011) x 1023 = 9.033 x 1023
