In a solid 'AB' having NaCl structure, 'A' atoms occupy the corners of the cubic unit cell. If all the face-centred atoms along one of the axes are removed,then the resultant stiochiometry of the solid is

Options

A. `AB_(2)`
B. `A_(2)B`
C. `A_(4) B_(3)`
D. `A_(3)B_(4)`

Answer

D

Explanation

No. of atoms (A) on the corners = 8
No. of atoms (A) on the face centres = 6
Removing face centred atoms along one of the axes means removal of 2A atoms so that
No. of A atoms per unit cell
`= 8 xx ( 1)/( 8 ) + 4 xx ( 1)/( 2) = 3 `
No. of B atoms per unit cell in NaCl type structure=4. Formula = `A_(3) B_(4)`