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For computer memory.
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.
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
As with other related rare-earth metals, gadolinium is silvery white, has a metallic
luster, and is malleable and ductile. At room temperature, gadolinium crystallizes in the
hexagonal, close-packed alpha form. Upon heating to 1235oC, alpha gadolinium transforms into the beta
form, which has a body-centered cubic structure.
The metal is relatively stable in dry air, but tarnishes in moist air and forms a
losely adhering oxide film which spalls off and exposes more surface to oxidation. The
metal reacts slowly with water and is soluble in dilute acid.
Gadolinium has the highest thermal neutron capture cross-section of any known element
Gadolinium yttrium garnets are used in
microwave applications and gadolinium compounds are used as phosphors in color television
The metal has unusual superconductive properties. As little as 1 percent gadolinium
improves the workability and resistance of iron, chromium, and related alloys to high temperatures
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. This suggests applications as a magnetic component that can sense hot and
Previous to 1993, the price of the metal was $485/kg.
Sources: CRC Handbook of Chemistry
and Physics and the American Chemical Society.