From gadolinite, a mineral named for Gadolin, a Finnish chemist. The rare earth metal is obtained from the mineral gadolinite. Gadolinia, the oxide of gadolinium, was separated by Marignac in 1880 and Lecoq de Boisbaudran independently isolated it from Mosander's yttria in 1886.
Gadolinium is found in several other minerals, including monazite and bastnasite, both of which are commercially important. With the development of ion-exchange and solvent extraction techniques, the availability and prices of gadolinium and the other rare-earth metals have greatly improved. The metal can be prepared by the reduction of the anhydrous fluoride with metallic calcium.
Gadolinium yttrium garnets are used in microwave applications and gadolinium compounds are used as phosphors in color television sets.
Gadolinium ethyl sulfate has extremely low noise characteristics and may find use in duplicating the performance of amplifiers, such as the maser.
The metal is ferromagnetic. Gadolinium is unique for its high magnetic movement and for its special Curie temperature (above which ferromagnetism vanishes) lying just at room temperature, meaning it could be used as a magnetic component that can sense hot and cold.
Natural gadolinium is a mixture of seven isotopes, but 17 isotopes of gadolinium are now recognized. Although two of these, 155Gd and 157Gd, have excellent capture characteristics, they are only present naturally in low concentrations. As a result, gadolinium has a very fast burnout rate and has limited use as a nuclear control rod material.