In which of the following structures coordination

In which of the following structures coordination number for cations and

anions in the packed structure will be same?

(i) Cl–ion form fcc lattice and Na+ ions occupy all octahedral voids of the unit cell.

(ii) Ca2+ ions form fcc lattice and F- ions occupy all the eight tetrahedral voids of the unit cell.

(iii) O2– ions form fcc lattice and Na+ions occupy all the eight tetrahedral voids of the unit cell.

(iv) S2– ions form fcc lattice and Zn2+ ions go into alternate tetrahedral voids

of the unit cell.