Gadolinium
Definition and meaning of Gadolinium in chemistry.
![Gadolinium element card: symbol Gd, atomic number 64, atomic mass 157.25, electron configuration [Xe] 4f⁷ 5d¹ 6s², oxidation states +3, Lanthanide, f-block, period 6, solid at room temperature.](/assets/images/terms/gadolinium-chemical-element.webp)
Gadolinium is a chemical element with the symbol Gd and atomic number 64. It is a silvery-white rare earth metal found in the lanthanide series. The pure metal is soft enough to bend and stretch easily without breaking.
In more detail
Gadolinium is a heavy metal that combines with other elements in nature. You can find it naturally in rare earth minerals like monazite and bastnasite. Chemists extract the pure metal using liquid solvents and an ion exchange process.
This heavy element sits in the f-block section of the modern periodic table. It contains a uniquely half-filled 4f electron subshell in its atomic structure. This specific electron arrangement gives gadolinium a remarkably strong and stable magnetic moment.
Its atomic nucleus can also absorb slow-moving thermal neutrons very easily and efficiently. The solid metal oxidizes very slowly when it is exposed to dry air. However, it loses its shine and tarnishes quite quickly in moist environments.
Gadolinium demonstrates highly unusual magnetic behavior when compared to most other elements. It acts like a strong permanent magnet at temperatures below 20 degrees Celsius. Above this specific temperature, called the Curie point, it becomes strongly paramagnetic.
Paramagnetic materials become temporarily magnetic only when placed inside an external magnetic field. This unique property makes gadolinium compounds extremely useful in modern medical technology. Chemically, the solid metal reacts directly with hot water to form gadolinium hydroxide.
This chemical reaction with hot water also releases highly flammable hydrogen gas. The solid gadolinium metal also dissolves very easily in weak, dilute acid solutions. The element typically forms clear, colorless salts in the +3 oxidation state.
Industries use these specific gadolinium salts to manufacture specialized optical glasses and lenses. They also use them to make phosphors, which are chemical materials that emit light.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Gd |
| Atomic number | 64 |
| Atomic mass | 157.25 u |
| Category | Lanthanide |
| State at room temperature | Solid |
| Melting point | 1312 °C |
Medical professionals safely inject Gadolinium(III) chelates into patients as intravenous contrast agents. These stable chemical complexes make internal organs much easier to see during MRI scans.
Frequently asked questions
Is gadolinium toxic?
Free gadolinium ions are highly toxic to humans. Doctors bind it into stable chemical complexes to ensure the body excretes it safely.
How does gadolinium affect MRI scans?
Its highly paramagnetic nature alters the magnetic properties of water in human tissues. This effect creates much brighter images on specific MRI scans.
Related terms
Sources & references
See our sources and editorial standards.