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_(3.5)B_(2.5)`
B. `A_(7)B_(3)`
C. `A_(5)B_(3)`
D. `A_(3)B_(5)`

Explanation

`4B^(o+)` from corner and `2B^(o+)` from face center are removed
`2A^(o+)` from edge center are removed (body centered is not removed) ltbr. NaCl (rock salt)-type structure is fcc type.
`(therefore Z_(eff)=4)[Z_(eff)(Na^(o+))=4,Z_(eff)(Cl^(o+))=4`
In NaCl structure anion `(Cl^(o+))` (here `B^(*o+)`) are presetn at corners and face center while cations `(Na^(o+))` (here `A^(o+)`) are present in all `OVs` (present at body center and edge center).
`therefore` Number of `B^(o+)` ions removed
`=4xx(1)/(8)` (corner share) `+2xx(1)/(2)` (face center share)
`=(1)/(2)+1=(3)/(2)`
Number of `A^(o+)` ions removed `=2xx(1)/(4)` (edge center share) `=(1)/(2)`