The radius ratio of Cs+ to Cl− is 0.90. If the radius of Cl− ion is 1.80 ∘A, the false statement regarding the CsCl structure is ?
The distance between Cs+ ion and Cl− is 3.60 ∘A
rCs+rCl−=0.90 ∘A⇒rCs+=0.90×rCl−=0.90×1.80=1.62 ∘A
For precise fitting of the cubic voids, rCs+rCl− must be 0.732 which is smaller than the given value of 0.90. Hence cubic packing of Cl− ions is loose to some extent, i.e., two Cl− ions are not in touch with each other and the distance between two Cl− ions will be greater than 3.60 ∘A.
The Cs+ ion at the centre of the body is in touch with 2Cl− ions at the opposite corners of the cube. Hence distance between Cs+ and Cl−=rCS++rCl−=1.62 ∘A+1.80 ∘A=3.42 ∘A