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Gadolinium is a chemical element; it has symbol Gd and atomic number 64. It is a silvery-white metal when oxidation is removed. Gadolinium is a malleable and ductile rare-earth element. It reacts with atmospheric oxygen or moisture slowly to form a black coating.
The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), [1] are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals. Compounds containing rare ...
Rare-earth ore, shown with a United States penny for size comparison. A rare-earth mineral contains one or more rare-earth elements as major metal constituents. Rare-earth minerals are usually found in association with alkaline to peralkaline igneous complexes in pegmatites. This would be associated with alkaline magmas or with carbonatite ...
The term rare-earth element or rare-earth metal is often used to include the stable group 3 elements Sc, Y, and Lu in addition to the 4f elements. [8] All lanthanide elements form trivalent cations, Ln 3+, whose chemistry is largely determined by the ionic radius, which decreases steadily from lanthanum (La) to lutetium (Lu).
Gadolinium(III) oxide (archaically gadolinia) is an inorganic compound with the formula Gd 2 O 3. It is one of the most commonly available forms of the rare-earth element gadolinium, derivatives, of which are potential contrast agents for magnetic resonance imaging. [2]
monazite-(Sm), (Sm,Gd,Ce,Th)PO 4, monazite-(Pr), (Pr,Ce,Nd,Th)PO 4. The elements in parentheses are listed in the order of their relative proportion within the mineral: lanthanum is the most common rare-earth element in monazite-(La), and so forth. Silica (SiO 2) is present in trace amounts, as well as small amounts of uranium and thorium.
Lepersonnite-(Gd) is a very rare-earth element and uranium mineral with the chemical formula Ca(Gd,Dy) 2 (UO 2) 24 (SiO 4) 4 (CO 3) 8 (OH) 24 ·48H 2 O.It occurs with bijvoetite-(Y) in the Shinkolobwe deposit in the Democratic Republic of the Congo, famous for rare uranium minerals.
Thirty-three radioisotopes have been characterized, with the most stable being alpha-decaying 152 Gd (naturally occurring) with a half-life of 1.08×10 14 years, and 150 Gd with a half-life of 1.79×10 6 years. All of the remaining radioactive isotopes have half-lives less than 100 years, the majority of these having half-lives less than 24.6 ...