• # question_answer 60) Sodium chloride, NaCI, usually crystallizes in a face- centred cubic lattice. How many ions are in contact with any single $\text{N}{{\text{a}}^{\text{+}}}$ion? A)  4                    B)  6C)  8                    D)  1

Since Nad has a fee structure, therefore each $N{{a}^{+}}$ion is surrounded by six $\text{C}{{\text{l}}^{-}}$ions at the corners of a regular octahedron and similarly each $\text{C}{{\text{l}}^{-}}$ion is surrounded by six Nations. It is therefore, termed as a 6 : 6 arrangement. Hence, the correct option is [b].