In a crystalline solid, anions `B` are arranged in ccp structure. Cations `A` are equally distributed between octahedral and tetrahedral voids if all the octahedral voids are occupied the formula of the ionic solids will be

Explanation

Anions y in ccp arrangement =4
Number of octahedral voids =4
Number of Tetrahedral voids =4
Cations x in Octahedral voids =4
Cations x in Tetrahedral voids=4
`therefore` Total cations x in tetrahedral void and octahedral void =8
`therefore` x:y
8:4
hence, formula is `x_2y`