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.
Option 2) The number of tetrahedral voids is twice the number of atoms per unit cell, and number of octahedral voids is equal to the number of atoms per unit cell. Hence, NaCl contains 4 × 2 = 8 tetrahedral voids and 4 octahedral voids.