(Solved): How to solve: Iron crystallizes in the BCC structure at room temperature with the mass density by ...

Iron crystallizes in the BCC structure at room temperature with the mass density by $?=7.86\mathrm{g}/{\mathrm{cm}}^3$ (a) Compute the radius of the iron atom in the BCC structure. (b) At temperature above $910^{?}\mathrm{C}$, iron is in the $\mathrm{FCC}$ structure. If we neglect the temperature dependence of the radius of the iron atom, we can then find the density of the iron in the FCC structure from that in the BCC structure. Determine whether iron expands or contracts when it undergoes the transformation from the BCC to FCC structure.