Question

The unit cell of a binary compound of A and B metals has a ccp structure with A atoms occupying the corners and B atoms occupying the centres of each faces of the cubic unit cell. If during the crystallisation of this alloy, in the unit cell two A atoms are missed, the overall composition per unit cell is :
A. `AB_(6)`
B. `AB_(4)`
C. `AB_(8)`
D. `A_(6)B_(24)`

Answer 1

Correct Answer - B
Number of atoms of A `=6xx(1)/(8)=(3)/(4)`
Number of atoms of `B=6xx(1)/(2)=3`
`A:B=(3)/(4):3=1:4`
`therefore` Composition of alloy `=AB_(4)`