A small part of a crystal lattice is sketched below. The unit cell is outlined in red.

Screenshot 2024 01 17 174948

Screenshot 2024 01 17 174948

Step 1 of 2

Given data: a small part of crystal lattice is given.

Find: atoms present in corner and face of a unit cell.


The number of atoms present in the corners and faces of a unit cell depends on the type of crystal lattice structure.

Step 2 of 2

Let’s assume:

The atom on corner grey = A
The smaller black atom = B

Total no of atom A: 8

It only has eight atoms present in the corners, each of which contributes 18

8×1/8=1 atom.

Total no of atom B: 2

It only has two atoms present in the face, each of which contributes 12

2×1/2=1 atom.


Hence we can add both the atoms to get the total no of atoms present in a unit cell.

Final solution


total no of contribution of atoms from the corner= 1

total no of contribution of atoms from the face= 1

hence total no of atoms in a unit cell is 1+1=2 atoms.


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