Question

A unit cell is obtained by closed packing layers of atoms in ABAB..... pattern.The total number of tetrahedral and octahedral voids in the unit cell are respectively

Answer 1

ABAB pattern suggests it is hcp lattice.

In a hcp lattice no. of atoms are 6

Thus total tetrahedral voids will be 12
Total octahedral voids will be 6.

Kindly confirm.

Answer 2

Answer:

The total number of tetrahedral and octahedral voids in the unit cell are 12 and 6 respectively.

Explanation:

Tetrahedral and octahedral voids are empty spaces found in substances with a tetrahedral or octahedral structural structure, respectively.

If A unit cell is made up of closed packing layers of atoms in the pattern $A B A B \ldots$, it is hexagonal close packing with $z=6$, i.e. the number of atoms per unit cell.

So, if we have $n$ atoms, the total number of tetrahedral and octahedral voids in the unit cell is,

$Tetrahedral voids = 2 \times 6=12 \\octahedral voids =6$

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