Question

in which of the following strutures corrding number for cations and anions in the packed structure will be same ?
A. `Cl^(-)` ions form fcc lattice and `Na^(+)` ions occupy all octahedral voids of the unit cell
B. `Ca^(2+)` ions form fcc lattice and `F^(-)` ions occupy all the eight tetrahedral voids of the unit cell
C. `O^(2-)` ions form fcc lattice and `Na^(+)` ions occupy all the eight tetrahedral voids of the unit cell
D. `S^(2-)` ions form fcc lattice and `Zn^(2+)` ions go into go into alternate tetrahedral voids of the unit cell

Answer 1

Correct Answer - A
NaCl crystal have rock salt structure having fcc lattice in which ` Cl^(-)` ions are present at fcc lattice points and face centre and `Na^(+)` occupies all the octahedral void of given unit cell
where , coordination number of `Na^(+)=6`
coordination of `Cl^(-)` = 6