A uni-univalent ionic crystal AX is composed of the following radii (arbitrary units) : {:(A^+,A^-),(1.0,2.0):} Assuming that ions are hard spheres , predict giving reasons whether the crystal will have sodium chloride cesium chloride structure. Calculate the volume of the unit cell.

A uni-univalent ionic crystal AX is composed of the following radii (a

1.	A uni-univalent ionic crystal AX is composed of the following radii (arbitrary units) : {:(A^+,A^-),(1.0,2.0):} Assuming that ions are hard spheres , predict giving reasons whether the crystal will have sodium chloride cesium chloride structure. Calculate the volume of the unit cell.
Answer» Solution :`r_(+)//r_(-)`=2/1=0.5 which LIES in the range 0.414-0.732 , HENCE , it has SODIUM chloride structure. Edge=2 `(r_++ r_-)` =6 au . Volume =`(6 au)^3=216(au)^3`