Iron is a polytropic material. At room temperature, it has a BCC crystal structure (alpha-iron or ferrite). Upon heating above 912C, it converts to a FCC crystal structure (-iron or austenite). If heated above 1394?C, it converts to a different BCC structure (?-iron). Calculate the lattice parameter for each of these unit cells using the atomic size information in the back of your book. Comment on the calculations for and iron is this method of calculation and the data used accurate or should some adjustments be made? Explain your answer.