Gadolinium (Gd) is found as a rare earth metal, which is tough to extract, and it appears like a silvery white crystal. It is one of the few metals with ferromagnetic properties at room temperature. Like most of the rare earth metals, gadolinium forms trivalent ions with fluorescent properties. Gadolinium is used for shielding in neutron radiography and in nuclear reactor as it absorbs neutrons. 更多
