Multiple choice The total number of tetrahedral voids per unit cell in NaCl is 4 8 Twice the number of octahedral voids Four times the number of octahedral voids None of these Reveal answer Fill a bubble to check yourself B Correct answer Explanation NaCl has FCC arrangement of Cl ions. Hence, the number of Cl ions in packaging per unit cell= 4 Tetrahedral is double of octahedral voids. Thus, 2n= 8.