Gadolinium
The MRI contrast metal with the best neutron shield in the periodic table.
Gadolinium pairs two superlatives: the highest thermal neutron capture cross-section of any stable element, and unusual paramagnetic behavior that makes gadolinium chelates the standard contrast agents in MRI scans. It also hardens alloys, enables magneto-optic recording, and serves in nuclear reactor shielding and emergency shutdown systems. Research into magnetic refrigeration — solid-state cooling built on gadolinium’s magnetocaloric effect — could open a substantial future market.
Uses
- Chelated gadolinium compounds are used as MRI contrast agents; this is not a use of free gadolinium metal.
- Strong neutron absorption supports nuclear shielding and control applications.
- Gadolinium is used in specialist alloys and electronic materials.
Key Facts
- Atomic number
- 64
- Flagship use
- MRI contrast agents
- Key property
- Highest neutron capture
- Emerging market
- Magnetic refrigeration
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Isotope reference
Isotopes & Nuclear Properties
Natural gadolinium includes long-lived radioactive Gd-152, which undergoes alpha decay. The other six natural isotopes are listed as stable in NUBASE2020.
| Isotope | Natural abundance | Half-life / status |
|---|---|---|
| ¹⁵²Gd | 0.204(2)% | 1.08(8) × 10¹⁴ years |
| ¹⁵⁴Gd | 2.187(9)% | Stable |
| ¹⁵⁵Gd | 14.828(60)% | Stable |
| ¹⁵⁶Gd | 20.493(22)% | Stable |
| ¹⁵⁷Gd | 15.657(17)% | Stable |
| ¹⁵⁸Gd | 24.820(20)% | Stable |
| ¹⁶⁰Gd | 21.811(28)% | Stable |
CIAAW amount-fraction uncertainties are shown in parentheses where reported. “Stable” means no radioactive half-life is assigned in this table.
Abundances are CIAAW amount fractions converted to percentages for normal terrestrial material; parentheses give uncertainty in the final digits. “Stable” means no decay is established in the cited evaluation, not that all decay modes are impossible. Natural abundance and nuclear stability do not establish chemical safety; enriched or activated material needs separate assessment.