Gadolinium

Gadolinium is a silvery-white lanthanide, part of the rare-earth metals. Like other lanthanides, it usually forms compounds with a +3 charge, but its magnetic behavior is unusual: near room temperature, the metal changes from ferromagnetic to strongly paramagnetic. In nature, gadolinium occurs in minerals such as monazite and bastnäsite, mixed with other rare-earth elements; despite its name, gadolinite contains only traces of it. To obtain it, ores are processed to dissolve and separate the rare earths, and gadolinium is then isolated from the mixture. Gadolinium compounds are used in MRI contrast agents, while the element’s strong neutron absorption makes it useful in some nuclear-reactor control and shielding applications.