Question

Sodium has body-centered packing. The distance between two nearest atoms is $3.7A^o$. The lattice parameter is:

• A. $8.6A^o$
• B. $6.8A^o$
• C. $4.3A^o$
• D. $3.0A^o$

Answer 1

The correct option is C $4.3A^o$

Let a be the lattice parameter, and r be the radius of one atom.

SInce, structure is of BCC type , we know that $4r=\sqrt{3}a$

The value of 2r has been given to be equal to $3.7A^o$

So, $2\times 3.7=a\sqrt{3}\Rightarrow a=4.3A^o$

So correct option is C