Gadolinium

Lore & Background

He designated the element with the provisional symbol Yα. Gadolinium is a member of the lanthanide series, with electron configuration [Xe]4f75d16s2. Gadolinium exhibits a magnetocaloric effect, and its compounds are used in phosphors and as MRI contrast agents due to paramagnetic properties. Naturally occurring gadolinium consists of six stable isotopes and the primordial radionuclide 152Gd, which has an extremely long half-life of 1.08×10^14 years. The element is found in minerals such as monazite and bastnäsite, and it is too reactive to exist in native form. Gadolinium metal is relatively stable in dry air but tarnishes in moist air, forming a loosely-adhering oxide coating.

Reader's Guide

Gadolinium's significance stems from its combination of magnetic, nuclear, and metallurgical properties. Below its Curie point of 20 °C, it is ferromagnetic with a magnetic attraction higher than nickel; above that, it is the most paramagnetic element, making it essential for MRI contrast agents. Chelated gadolinium(III) compounds are used intravenously in medical imaging because they are paramagnetic and, when chelated, are excreted by healthy kidneys before depositing in tissues. In nuclear reactors, gadolinium's high neutron capture cross-section (especially 157Gd) makes it valuable for shielding and control rods. As little as 1% gadolinium improves the workability and oxidation resistance of iron, chromium, and related metals at high temperatures. Gadolinium also serves as a phosphor in medical imaging, a gamma ray emitter, and in electronic, optical, and superconducting devices. The element's toxicity in ionic form is mitigated by chelation, allowing safe medical use. Overall, gadolinium bridges fundamental physics, materials science, and practical medical technology.

Did You Know?

• Gadolinium is ferromagnetic below 20 °C and the most paramagnetic element above that temperature.
• As little as 1% gadolinium can significantly improve the workability and resistance to oxidation at high temperatures of iron, chromium, and related metals.