Question

The structure of NaCl crystal is

• A. Hexagonal close packing
• B. Face centred cubic
• C. Square planar
• D. Body centred cubic

Hint:

Ionic compounds like NaCl often form face-centred cubic (FCC) structures, where each ion is surrounded symmetrically by six oppositely charged ions.

Answer 1

The Correct Option is B

Step 1: Understanding the NaCl crystal structure.
The structure of sodium chloride (NaCl) is face-centred cubic (FCC), where each sodium ion is surrounded by six chloride ions and vice versa, in a 3D arrangement. This arrangement is characteristic of an FCC lattice. Step 2: Analysis of options.
(A) Hexagonal close packing: This is a structure where particles are closely packed in a hexagonal arrangement. NaCl does not follow this structure.
(B) Face centred cubic: Correct — NaCl adopts a face-centred cubic (FCC) lattice, which is one of the most common structures for ionic crystals.
(C) Square planar: This is not the correct structure for NaCl, as square planar arrangements occur in two-dimensional structures.
(D) Body centred cubic: This is not the correct arrangement for NaCl, as it does not form a body-centred cubic structure.
Step 3: Conclusion.
The correct answer is (B) because NaCl has a face-centred cubic crystal structure.