A compound forms hexagonal close packed …

Number of atoms in close packaging = 0.5 mol 1 has 6.022×10 23 particles So that Number of close-packed particles =0.5×6.022×10 23 =3.011×10 23 Number of tetrahedral voids = 2 × number of atoms in close packaging Plug the values we get Number of tetrahedral voids =2×3.011×10 23 =6.022×10 23 Number of octahedral voids = number of atoms in close packaging So that Number of octahedral voids =3.011×10 23 Total number of voids = Tetrahedral void + octahedral void =6.022×10 23 +3.011×10 23 =9.03×10 23