Lithium has a bcc structure. Its density is 530kg m ^ - 3 and its...

$d = \dfrac{ZM}{{N}_{A}{a}^{3}}$

${a}^{3} = \dfrac{6.94 \times 2}{{6.022 \times 10}^{23} \times 530 \times {10}^{- 3}} = \dfrac{6.94 \times 200 \times {10}^{- 24}}{5.30 \times 6.022}$

$= 3.52 \times {10}^{- 8}cm$

$= 352pm$