What is the coordination number of Na⁺ and Cl⁻ ions in NaCl lattice ?

What is the coordination number of Na⁺ and Cl⁻ ions in NaCl lattice ?

[amp_mcq option1=”6, 1″ option2=”1, 6″ option3=”6, 6″ option4=”5, 5″ correct=”option3″]

This question was previously asked in
UPSC NDA-1 – 2024
In the NaCl crystal lattice, both Na⁺ and Cl⁻ ions have a coordination number of 6.
The NaCl crystal structure is a face-centered cubic (FCC) arrangement where each Na⁺ ion is octahedrally surrounded by six Cl⁻ ions, and similarly, each Cl⁻ ion is octahedrally surrounded by six Na⁺ ions.
The coordination number in an ionic lattice refers to the number of oppositely charged ions immediately surrounding a given ion. This coordination number is determined by the relative sizes of the ions and the need to maximize electrostatic attraction while minimizing repulsion.