Q. Sodium has body centred packing. Distance between two nearest atoms is 3.7 Å. The lattice parameter is:
A) 4.3 Å
B) 3.0 Å
C) 8.6 Å
D) 6.8 Å
Explanation
[Solution from source] In a bcc lattice the nearest neighbours lie along the body diagonal, so 2r = d = √3a/2. a = 2 × 3.7/√3 ≈ 4.27 ≈ 4.3 Å. Doubling 3.7 Å treats the structure as touching along the cube edge. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.