Chemistry - Solid State Question with Solution | TestHub

Question Explanation:

Determining the vertical positions of tetrahedral voids in an HCP cell. ×

Concept:

Tetrahedral voids in Hexagonal Close Packed structure.

Solution:

In an HCP unit cell ( ABAB pattern), the distance between any two consecutive layers is $\mathrm{h}/2$.

Tetrahedral voids are located between these layers at heights of $1/4$ and $3/4$ of the interlayer distance.

Total height $=\mathrm{h}$; Interlayer distance $=\mathrm{h}/2$.

Heights from the base:

- First layer of voids: $\frac{1}{4}\times \frac{h}{2}=\frac{h}{8}and\frac{3}{4}\times \frac{h}{2}=\frac{3h}{8}$

- Second layer of voids: $\frac{h}{2}+\frac{h}{8}=\frac{5h}{8}and\frac{h}{2}+\frac{3h}{8}=\frac{7h}{8}$

Among the given choices, the pair 3h/8 and 5h/8 represents standard void positions.