# A compound formed by elements X and Y has a cubic structure in which X atoms are at the corner of the cube and Y atoms are at the face centres.(b) If all the atoms are removed from a single axis passing through the centre of the cube,calculate (i) $Z_{eff}$, (ii) total number of atoms in a cube, and (iii) formula of the compound.

(i)3,(ii)12,(iii) $XY_3$