Question

a compound forms hexagonal close packed structure. what is the total no. of voids in 0.5 mol. of it ? how many of these are tetrahedral voids?

Answer 1

We know that 1 mole of hexagonal packed structure contains 1 mole of octahedral voids and two moles of tetrahedral voids,

Therefore 0.5 moles of hexagonal packed structure contains 0.5 moles of octahedral voids and 1 mole of tetrahedral voids,

No. of tetrahedral voids = 6.022 x 10²³

No. of octahedral voids = ½ x No. of tetrahedral voids

No. of octahedral voids = ½ x 6.022 x 10²³

= 3.011 x 10²³

Total no. of voids = (6.022+3.011) x 10²³

= 9.033 x 10²³