LEAD IS A MEMBER of Group IVB of the periodic table with two oxidation states (Pb2+ and Pb4+), but the chemistry of the element is dominated by Pb2+ ion. Lead has four isotopes with three of them being the ultimate decay products of uranium (238U and 235U) and, therefore, widely used in geological dating. The crystal structure of lead in solid form is face-centered cubic (FCC) with a lattice parameter of 4.95 Å at 20°C. Lead is a blue-gray metal with density (11.3 g/cm3) 50 % more than that of steel and four times that of aluminum. However, lead is malleable, soft, and melts at only 327°C, and therefore, readily cut and shaped into pipes and sheets since ancient times.