Periodic Table -> Gadolinium


Gadolinium Details

Gadolinium Symbol: Gd

Gadolinium Atomic Number: 64

Gadolinium Atomic Weight: 157.25

What is Gadolinium?

Gadolinium bears the symbol Gd and is listed under number 64 in the periodic table. It is ductile, malleable, and silvery-white in color. Gd is one of the rare Earth metals, which is more abundant, but it does not occur naturally on its own. This metal was discovered in 1880 following its separation. It was found in the mineral gadolinite, which is where it gets its name. The major mining sites are in the United States, China, Australia, India, Sri Lanka, and Brazil. Reserves are assessed at over 1 million tonnes, while production of gadolinium stands at about 400 tonnes a year worldwide. Similar to other lanthanides, gadolinium forms compounds that are moderately toxic. The salts of gadolinium irritate the eyes and skin, and they may be tumorigens.

This metal has some very useful properties, however, making its application quite feasible. For example, less than one percent of the metal improves the resistance and workability of chromium, iron, and other similar alloys to oxidation and high temperatures. It absorbs neutrons at a very high rate, thus making its use in nuclear reactors very effective and viable. The trivalent ions that this metal forms are used as phosphors because of their fluorescent properties, which is something typical of rare earth metals.

One isotope of gadolinium, Gd-157, has the highest thermal neutron capture of all stable nuclides. It reaches 259,000 barns. The only element with a higher cross section is an isotope of xenon, xenon-135, which is rather unstable.

Gadolinium attracts iron objects at temperatures lower than 20 C (68 F). When it enters a magnetic field, its temperature increases. When it leaves the field, it decreases correspondingly.

In combination with other elements, gadolinium forms what are known as Gd (III) derivatives. These include boron, nitrogen, phosphorus, and carbon. Other derivatives are selenium, sulfur, silicon, and arsenic. It forms the gadolinium (III) oxide when it interacts with moist air.

Usually this element adopts the oxidation state +3. This means it features four trihalides, all of which are known. Salts such as gadolinium (III) nitrate are produced when the oxide of the element dissolves in acids.
Gadolinium acts as a very powerful reducing agent, reducing the oxides of a number of metals into their elements. Gadolinium exhibits a slow reaction with cold water and a very fast one with hot water, whereby gadolinium hydroxide is formed. Gadolinium is used in control rods for nuclear power plants as well as nuclear reactors. It is also used in the production of garnets for various microwave applications. The production of phosphorous used in color TV tubes involves compounds of gadolinium. Metallic gadolinium is not used as often as the metal; however, electronic components and magnets are made by using its alloys. Alloys are used for components like recording heads for video recorders. Computer memory and compact discs are also produced using gadolinium.

Gadolinium has a range of specialized uses, among which targetting tumors in neutron therapy in medicine, as a back-up shut-down measure in nuclear reactors, and in nuclear marine propulsion systems.

Gd has six stable isotopes and one radioactive isotope. The most frequently found isotope in nature is Gd-158. The others are 154, 155, 156, 157 and 160. The radioactive one is Gd-152.

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