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 corrent atom `(A) = A xx (1)/(8) = 1 = X`
Effective number of face corrent atom `(B)`
`= (1)/(2) xx 6 = 3 = Y`
Thus composition of substance` = AB_(3)`