The number of tetrahedral voids per unit cell in NaCl crystal is ________.
(i) 4
(ii) 8
(iii) twice the number of octahedral voids.
(iv) four times the number of octahedral voids.
The answer is the option (ii, iii) NaCl has fcc arrangement
Number of atoms in packing per unit cell = 4
Number of tetrahedral voids per unit cell = 2 No. of particles present in close packing
Number of tetrahedral voids per unit cell = 2 No. of octahedral voids
Hence, option ii and iii are correct.