In a cubic crystal, A-atoms are placed at every corner and B-atoms at the centre of every face. The formula of the compound is
- AB
- AB3
- A2B2
- A2B3
Answer
(2) AB3
Solution
∵ A corner atom is shared by 8 unit cells and a face-centre atom by 2 unit cells.
Number of A atoms per unit cell = 8 18 = 1
Number of B atoms per unit cell = 6 12 = 3
∴ A : B = 1 : 3 ⇒ formula AB3
Answer: (2)