gadolinio

Gadolinium (symbol Gd, atomic number 64) is a chemical element in the lanthanide series and the rare-earth elements. It occurs in trace amounts in the Earth's crust and is primarily obtained from minerals such as gadolinite and monazite through chemical separation and processing.

Gadolinium is a silvery-white metal that is relatively soft for a lanthanide. It is trivalent in most compounds (Gd3+) and is highly paramagnetic, with a large magnetic moment at room temperature. Its neutron capture cross-section is notably large for the isotope Gd-157, a property exploited in nuclear technology and shielding applications.

Natural gadolinium comprises several stable isotopes and is produced commercially by refining rare-earth ores and separating it from other lanthanides. The element’s name derives from the mineral gadolinite, which was named after the Finnish chemist Johan Gadolin.

Applications include medicine, where gadolinium is used in gadolinium-based contrast agents for magnetic resonance imaging (MRI). In nuclear technology, gadolinium serves as a neutron absorber in control rods and shielding materials. It is also studied for magnetocaloric effects and is used in certain phosphors and lighting materials.

Safety and regulation emphasize that gadolinium salts are toxic if ingested, but in MRI contrast agents the gadolinium ion is tightly chelated to reduce toxicity. In patients with kidney impairment, there is a risk of nephrogenic systemic fibrosis and related deposition issues, which has led to monitoring guidelines and screening prior to contrast administration.