Body-centered cubic (BCC) is the name given to a type of atom arrangement found in nature. A body-centered cubic unit cell structure consists of atoms arranged in a cube where each corner of the cube shares an atom and with one atom positioned at the center.
$\sqrt{3}\mathrm{a}=4\mathrm{r}$ (for bcc lattice)
$\mathrm{r}=\frac{\sqrt{3}}{4}\times 288 \mathrm{pm}$