A compound formed by elements X and Y crystallizes in the cubic structure, where X atoms are at the corners of a cube and Y atoms are at the centres of the body. The formula of the compound is :
(A) XY
(B) XY2
(C) X2Y3
(D) XY3
Correct Answer – XY
As there are 8 Y atoms at the corners and contribution of each =`1/8`, therefore , no. of Y atoms/unit cell `=8xx1/8=1` . There can be only two X atoms on alternate faces. As contribution of each of them =`1/2`, therefore, no. of X-atoms/unit cell =`2xx1/2=1`. Hence, formula is XY
The correct option (A) XY
Explanation:
X = 8 x 1/8 = 1 (at corner)
Y = 1 × 1 = 1 (at body center)
So formula of compound = XY