Q 1.15: A compound forms hexagonal close−packed structure. What is the total number of voids in 0.5 mol of it? How many of these are tetrahedral voids?

Q 1.15: A compound forms hexagonal close−packed structure. What is the total number of voids in 0.5 mol of it? How many of these are tetrahedral voids?

Solution:

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 × 10²³ = 3.011 × 10²³

Number of tetrahedral voids = 2 × number of atoms in close packaging

Plug the values we get

Number of tetrahedral voids = 2 × 3.011 × 10²³

                                                  = 6.022 × 10²³

 Number of octahedral voids = number of atoms in close packaging

So that

Number of octahedral voids = 3.011 × 10²³

Total number of voids = Tetrahedral void + octahedral void

                                       = 6.022 × 10²³ + 3.011 × 10²³ 

                                       = 9.03 × 10²³