Question

The unit cell of an ionic compound is a cube in which cations (A) occupy each of the corners and anions (B) are at the centres of each face . The simplest formula of the ionic compound is

(a) AB₂ 

(b) A₃ B 

(c) AB₃ 

(d) A₄ B₃

Answer 1

Correct option: (c) AB₃

Explanation:

Number of A atoms per unit cell = 1/8 x 8 = 1

(An atom at corner is shared by 8 unit cells)

Number of B atoms per unit cell = 1/8 x 6 = 3

(An atom at the face centre is shared by 2 unit cells)

Hence, formula is : AB₃