Gadolinium is a rare earth metal. It is silver gray, malleable and ductile at room temperature.

It crystallizes in hexagonal form at room temperature, but has another allotropic form known as the beta form, with a cubic structure centered above 1 508 K.

Gadolinium is fairly stable in dry air. However, it oxidizes quickly in humid air. Gadolinium reacts slowly with water and is soluble in dilute acids.

Gadolinium oxide was isolated in 1880 by Jean Charles Galissard de Marignac, and Paul-Émile Lecoq de Boisbaudran prepared pure metal in 1886. It is named in honor of the Finnish chemist Johan Gadolin7, a.

Gadolinium is classically considered to be one of the four ferromagnetic elementsb but its TC Curie point is very low (around 292 K, or 19 กใ C). The real nature of this magnetism ordered below TC is disputed8.

Gadolinium has the greatest absorption capacity for thermal neutrons among all natural elements (49 kilobarns1).

Gadolinium has some toxicity. In fact, it competes with calcium in the calcium-dependent processes of the human body (breathing, heartbeat, muscle contraction, coagulation ...) and can lead to serious damage depending on its concentration. This is why the gadolinium compounds which are used in medicine as a contrast agent for magnetic resonance imaging (MRI) are necessarily complexed.

Gadolinium is characterized by a particularly low mineralogical diversity: only one mineral is known of which it is an essential constituent, lepersonnite- (Gd). It is rather found in solid solution in various minerals rich in rare earths. Today it is mainly extracted from monazite (Ce, La, Th, Nd, Y) PO4 and bastnäsite (en) (Ce, La, Y) CO3F.

Alloys: Gadolinium (up to 1%) is added to chromium steel to improve hardness and processing properties.
Gd3Ga5O12 gadolinium-gallium garnet (GGG) is used to make lasers, once doped with neodymium, ytterbium or dysprosium. Developments are underway to develop X-ray lasers with Nd: GGG. GGG is also used as a substrate for the fabrication of thin film microwave components (ferrites).
Phosphorescent substance in cathode ray tubes.
Superconductive alloys.
Contrast agent in magnetic resonance imaging (MRI) where it is associated with a chelator or a ligand. This product tends to accumulate in the brain without its toxicity being fully known9. Certain gadolinium chelates (macrocyclic agents) do not cause a neurological deficit10. In addition, this heavy metal is toxic (even fatal) for people with kidney disease and can cause an inflammatory reaction11.
Neutron absorbent:
in its oxidized form Gd2O3 in certain nuclear reactors in order to limit reactivity at the start of life thanks to the neutron absorbing properties of the isotopes 155Gd (61 kilobarns1) and especially 157Gd (254 kilobarns1) which by capture are transformed into the isotope 156Gd and 158Gd, practically non-absorbent (cross sections of the order of the barn). The kinetics of wear of Gadolinium is very specific (skin effect) indeed under irradiation its neutron weight remains fairly constant until a breaking point where its effectiveness decreases very quickly.
In 2019, gadolinium was added to the water of the Japanese super-Kamiokande neutrino observatory in order to be able to detect the neutrons produced by collisions between antineutrinos emitted by supernovas and protons present in water molecules12.
French team tests refrigerator that works by magnetizing this material


rhenium    germanium    zirconium     cadmium     hafnium

      barium   lithium     beryllium     strontium     calcium

      Tantalum    gadolinium    samarium      yttrium   ytterbium

       Lutetium    praseodymium   holmium     erbium   thulium     dysprosium

       terbium   europium  lanthanum   cerium   neodymium  scandium 

         rubidium    cesium