The atomic radius of nickel is 124 pm and the average atomic mass of nickel is 58.6934 amu. Calculate the density of nickel assuming a simple cubic, body-centered cubic, and face-centered cubic unit cell structures. Now, the experimental density of nickel under normal conditions of temperature and pressure is 8.908 cm^-3. Predict its crystal structure, and use the experimental density to obtain an experimentally-corrected atomic radius.