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?

Answer

Total number of viods `= 9.033 xx 10^(23)`
Number of tetrahedral viods `= 6.022 xx 10^(23)`

Explanation

Number of atoms in the close packing `= 0.5 mol = 0.5 xx 6.022 xx 10^(23) = 3.011 xx 10^(23)`
Number of octahedral voids = Number of atoms in the packing ` = 3.011 xx 10^(23)`
Number of tetrahedral voids `= 2 xx` Number of atoms in the packing `= 2 xx 3.011 xx 10^(23) = 6.022 xx 10^(23)`
Total number of viods `= 3.022 xx 10^(23) + 6.022 xx 10^(23) = 9.02 xx 10^(23)`