A swubstance `A_(x)B_(y)` crystallises in a face cubic centred cubic (fcc) lattice in which `A` occupy each corner of the cube and atoms `B` occapy the centers of each face of the ci=ube identical the correct composition of the substance `A_(x)B_(y)`

Options

A. `AB_(3)`
B. `A_(4)B_(3)`
C. `A_(3)B`
D. Composition cannot be specified

Answer

A

Explanation

Effective number of corner atoms `A=8xx(1)/(8)=1`
Effective number of face centred atom `B=(1)/(2)xx6=3`
Thus the composition will be `AB_(3)`.