In a solid having rock salt structure, if all tge atoms touching one body diagonal plane are removed (except at body centre), then the formula of the left unit cell is

Options

A. `A_(7)B_(3)`
B. `A_(5)B_(3)`
C. `A_(5)B_(3)`
D. `A_(7//2)B_(5//2)`

Explanation

PQRS is the body diagonal plane
‘B’ atoms are at corners and face centres
No. of B atoms left `=4-((1)/(8)xx4+(1)/(2)xx2)=(5)/(2)`
'A' are at edge centres + body centre
No. of 'A' atoms left `=4-((1)/(4)xx2)=(7)/(2)`
The formula of the compound is : `A_(7//2)B_(5//2)`