gadolin

Gadolin, or gadolinium (symbol Gd), is a chemical element with atomic number 64. It is a silvery-white lanthanide metal that is relatively soft and highly conductive. The element was first identified in 1880 by Jean Charles Galissard de Marignac, who separated its oxide from gadolinite. In 1886, Paul-Émile Lecoq de Boisbaudran isolated the element and named it gadolinium after gadolinite, the mineral in which the element was found. The name ultimately honors Johan Gadolin, a Finnish chemist.

Gadolinium occurs naturally in minerals such as gadolinite, monazite, bastnäsite, and xenotime, and is one of the rare-earth elements. It is typically recovered as a byproduct of processing these minerals. The element most commonly exists in the +3 oxidation state in compounds, though other oxidation states can occur in specialized environments.

Physically, gadolinium has a melting point of about 1313°C and a boiling point around 3273°C, with a density near 7.9 g/cm³. It is highly paramagnetic due to its seven unpaired f-electrons and becomes ferromagnetic just above room temperature, a property of interest in research. In practical use, gadolinium is valued for its large neutron capture cross-section and for biomedical applications.

Major applications include gadolinium-based contrast agents for magnetic resonance imaging (MRI), which exploit the element’s magnetic properties. It is also used in nuclear reactors for neutron shielding and control due to its neutron-absorbing capability, and in certain phosphors and specialty magnets. Safety considerations center on the potential risk of nephrogenic systemic fibrosis in patients with kidney impairment when gadolinium is used as a contrast agent.

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