In a solid 'AB' having NaCl structure atoms occupy the corners of the cube unit cell. If all the face centred atoms along one of the axis are removed then the resultant stoichiometryof the solid is

In a solid 'AB' having NaCl structure atoms occupy the corners of the

1.	In a solid 'AB' having NaCl structure atoms occupy the corners of the cube unit cell. If all the face centred atoms along one of the axis are removed then the resultant stoichiometryof the solid is
Answer» `AB_(2)` `A_(2)B` `A_(4)B_(3)` `A_(3)B_(4)` Solution :In one NaCl type unit cell of solid `B^(-)`are present at corners and face centred and `A^(+)` are present at edge centres and body centre. Thus, a unit cell will contain 4 `A^(+)and 4B^(-)`ions. In this unit TWO face centred ions `B^(-)`lies along one axis and are REMOVED. Contribution of two FECE centred `B^(-)`ions `=2times1//2=1` In the resultant unit cell, `THEREFORE "No.of " A^(+)` ions present per unit cell =4 `therefore"No. of "B^(-)`ions present per unit cell =4-1=3resultant. `therefore"Stoichiometry"=A_(4)B_(3)`