Atomic Properties of Gd
- Atomic Number of Gd
- 64
- Atomic Mass of Gd
- 157.2500 u
- Electron Configuration
- [Xe] 4f7 5d1 6s2
- Electronegativity
- 1.20
- Block
- f-block
- Group
- —
- Period
- 6
Jean Charles Galissard de Marignac detected gadolinium's distinct spectrum in 1880. The name came through the mineral gadolinite, which honored Finnish chemist Johan Gadolin. Its modern identity rests on an unusually strong magnetic response created by seven unpaired 4f electrons in Gd3+.
That response makes gadolinium useful in MRI contrast agents. An administered compound can change how nearby water protons relax, helping selected tissues or blood vessels stand out in an image. Crucially, clinical agents bind Gd3+ inside a chelating molecule. Free gadolinium ions are toxic, and agent choice and use require medical judgment, especially for patients with severely impaired kidney function. “Gadolinium dye” hides the chemistry that makes the application possible.
Gadolinium also has unusual elemental magnetism: it becomes ferromagnetic below a Curie temperature near room temperature. Its stable isotopes gadolinium-155 and gadolinium-157 capture neutrons exceptionally strongly, supporting specialized reactor, detector, and research applications. These magnetic and nuclear properties are separate phenomena, even though both make the element sensitive to its environment.
The silvery metal reacts with air and is not what patients receive in an MRI injection. Medical use involves formulated compounds at controlled doses.
This Luminary makes the invisible visible through disciplined restraint. Seven unpaired electrons create the contrast opportunity; coordination chemistry keeps the useful ion on a molecular leash. The clearest story includes both halves, because image quality and safe design arise from the same deliberate compound.