Gadolinium

Gadolinium was officially discovered in 1880, but it might have been found sooner! The element takes its name from gadolinite, a mineral that was in turn named after Johan Gadolin, a Finnish chemist and mineralogist. Gadolinite was named after Gadolin in recognition of the fact that he discovered the element yttrium from a sample of gadolinite in 1792. But Gadolin missed the other nine new elements that were also inside the mineral!

Element 64 was one of those hidden elements, but in fairness it's only present in gadolinite in very small amounts. Gadolinium was ultimately found in the mineral by Swiss chemist Jean Charles Galissard de Marignac in a sample almost 90 years later. De Marignac named the element after the gadolinite and, by extension, after Gadolin. Although Gadolin didn't discover element 64, he still ended up having the element named after him!

Gadolinium is a silvery white metal. It is malleable, which means that it can be easily shaped, and ductile, meaning that it can stretch without breaking. In moist air, gadolinium tarnishes quickly. The element is also highly magnetic.

Mixing gadolinium into metals like iron or chromium can make those metals easier to work with. Because gadolinium is great at absorbing neutrons, it’s often used in nuclear reactors. Gadolinium is also used in magnetic resonance imaging (MRI). By injecting a gadolinium mixture into a patient’s bloodstream, doctors can more easily see inside a patient’s body. About one third of MRIs involve the use of gadolinium!

Gadolinium is also useful for making magnets and electronics like compact discs. Gadolinium yttrium aluminum garnets are a type of crystal that’s often used in lasers.

Gadolinium forms most of its compounds in its +3 oxidation state (meaning it loses three of its electrons). Many of these compounds are useful in MRI imaging.

In the past, other gadolinium compounds were used in television tubes. However, this use has declined because new televisions don’t use tubes. 

In nature, gadolinium is found in six stable (non-radioactive) isotopes—gadolinium-154, gadolinium-155, gadolinium-156, gadolinium-157, gadolinium-158, and gadolinium-160, along with one unstable, or radioactive isotope, gadolinium-152. About a quarter of naturally occurring gadolinium is in the form of gadolinium-160.

Altogether, 33 radioactive gadolinium isotopes have been observed. The most stable—naturally-occurring gadolinium-152—has a half-life of 1.08×10¹⁴ years. Most of the other isotopes have half-lives of less than 25 seconds.

Gadolinium is a rare-earth element that’s found alongside many other rare-earth elements, such as monzanite and bastnäsite. Although the element is technically named after the mineral gadolinite, gadolinium is only a trace element in that mineral.

Most commercially produced gadolinium comes from China, the United States, Brazil, Sri Lanka, India, and Australia.