Question

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 1

Hey there!

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Answer :

1 mole of hexagonal packed structure contains 1 mole of octahedral voids and 2 moles of tetrahedral voids. 0.5 mole of hexagonal packed structure contains 0.5 mole of octahedral voids and 1 mole of tetrahedral voids.

Number of tetrahedral voids = 6.022 × $10^{23}$

Number of tetrahedral voids = 2 × No. of octahedral voids

Number of octahedral voids = $\frac{1}{2}$ × Number of tetrahedral voids.

= $\frac{1}{2}$ × 6.022 × $10^{23}$

= 3.011 × $10^{23}$

= Total number of tetrahedral and octahedral voids

= 6.022 × $10^{23}$ + 3.011 × $10^{23}$

= 9.033 × $10^{23}$