A unit cell consists of a cube in which there are a atom at the corner and b atom at the face centred and a atom are missing formed 2 corners in each unit cell . what is the simplest formula of the component
Answers
Given:
- The given unit cell is Face Centred Cubic unit cell.
- a atoms are at corner and b atoms are at face centre.
- a atoms are missing at 2 corners in each unit cell.
To Find:
Formula of compound.
Calculation:
- Since two a atoms are missing in each unit cell
⇒ No of a atoms in each unit cell = 8 - 2 = 6
- Contribution of an atom at corner = 1/8
⇒ Contribution of a atoms in each unit cell = 1/8 × 6 = 3/4
- No of b atoms in each unit cell = 6
- Contribution of an atom at face centre = 1/2
⇒ Contribution of b atoms in each unit cell = 1/2 × 6 = 3
- Formula of compound is given by:
a : b = 3/4 : 3
⇒ a : b = 1 : 4
- So the formula of compound is ab₄
Answer:
Here,
No. of A atoms = 1/8 ×(8-2)
=3/4 [ since 2 atoms are missing from the two corners]
No. of B atoms = 1/2 ×6 = 3
Explanation:
Now, Ration of A: B= 3/4 : 3
= 1 : 4
Therefore the formula of the compound is AB4