125
57
104
183
According to the given figure, A⁺ is present in the octahedral void of X⁻. The limiting radius in an octahedral void is related to the radius of the sphere as:
Radius of cation (A⁺) / Radius of anion (X⁻) = 0.414
Given that the radius of X⁻ is 250 pm, we can calculate the radius of A⁺:
Radius of A⁺ = 0.414 × Radius of X⁻
Radius of A⁺ = 0.414 × 250 pm
Radius of A⁺ = 103.5 pm
The closest option to 103.5 pm is 104 pm.