Gadolinium
Gadolinium is a rare-earth metal with notable magnetic behaviour and a strong ability to absorb neutrons.
Gadolinium connects magnetic behaviour with specialist imaging chemistry.
Explore Gadolinium's atom- Atomic number
- 64
- Standard atomic weight
- 157.249(2)
- Family
- Lanthanide
- Period
- 6
- Group
- f-block
- Standard state
- Solid
In everyday life
Gadolinium compounds are used in some MRI contrast agents.
Something to remember
Gadolinium is especially effective at absorbing neutrons.
Meet its electrons
[Xe] 6s2 4f7 5d1
Published neutral-atom ground-state configuration; excited atoms and ions can differ.
Electrons per shell: 2 · 8 · 18 · 25 · 9 · 2.
The playground shows an illustrative shell model. Real electrons are described by quantum orbitals, rather than tiny planets traveling along fixed paths.
A connection to explore
Small additions of gadolinium can change the properties of iron-containing alloys.
Meet Iron (Fe)Properties and conditions
- Standard atomic weight
- 157.249(2)CIAAW 2024 standard atomic weight (dimensionless). Parentheses give uncertainty in the last quoted digits. Source flags: g.CIAAW standard atomic weights ↗ · Retrieved 2026-10-15
- Standard state
- SolidPubChem classification, including explicit predictions where stated. Reference temperature and pressure are not supplied in the table.PubChem periodic table ↗ · Retrieved 2026-10-15
- First ionisation energy
- 6.150 eVEnergy to remove the first electron from an isolated neutral gas-phase atom. Uncertainty is not supplied.PubChem periodic table ↗ · Retrieved 2026-10-15
- Electronegativity
- 1.2 Pauling scaleA dimensionless relative measure; values depend on the chosen scale. Uncertainty is not supplied.PubChem periodic table ↗ · Retrieved 2026-10-15
- Melting point
- 1586 KPubChem reported value. Pressure, allotrope and measurement uncertainty are not specified in the table; consult the cited source.PubChem periodic table ↗ · Retrieved 2026-10-15
- Boiling point
- 3546 KPubChem reported value. Pressure and measurement uncertainty are not specified in the table; consult the cited source.PubChem periodic table ↗ · Retrieved 2026-10-15
- Density
- 7.90 g/cm³PubChem reported value. Temperature, pressure, allotrope and measurement uncertainty are not specified in the table; gas densities are especially condition-dependent.PubChem periodic table ↗ · Retrieved 2026-10-15
- Oxidation states
- +3Selected PubChem oxidation states; formal electron bookkeeping, not a list of stable free-ion charges or every possible compound.PubChem periodic table ↗ · Retrieved 2026-10-15
- Discovery
- 1880PubChem discovery attribution. Ancient knowledge and competing priority claims cannot always be represented by a single year.PubChem periodic table ↗ · Retrieved 2026-10-15
- Atomic radius
- 237 pmPubChem tabulated radius. Radius definitions depend on bonding and convention; measurement definition and uncertainty are not supplied in this table.PubChem periodic table ↗ · Retrieved 2026-10-15
- Electron affinity
- Not reportedPubChem reported gas-phase electron affinity. Sign conventions and electronic states matter; uncertainty is not supplied in this table.PubChem periodic table ↗ · Retrieved 2026-10-15
Isotopes, abundance and decay
Isotopes share a proton count but have different neutron counts. This selection includes naturally tabulated compositions and a reference isotope for other elements. It is not a list of every known isotope.
Explore 7 isotopes of Gd
| Isotope | Relative atomic mass | Natural fraction | Half-life | Decay |
|---|---|---|---|---|
| Gd-152 | 151.9197995(18) | 0.0020(1) | 108 Ty (uncertainty 8) | ;α=100;2β+ ? |
| Gd-154 | 153.9208741(17) | 0.0218(3) | No decay observed | No decay tabulated |
| Gd-155 | 154.9226305(17) | 0.1480(12) | No decay observed | No decay tabulated |
| Gd-156 | 155.9221312(17) | 0.2047(9) | No decay observed | No decay tabulated |
| Gd-157 | 156.9239686(17) | 0.1565(2) | No decay observed | No decay tabulated |
| Gd-158 | 157.9241123(17) | 0.2484(7) | No decay observed | No decay tabulated |
| Gd-160 | 159.9270624(18) | 0.2186(19) | No decay observed | ;2β− ? |
Fractions use NIST’s terrestrial isotopic compositions, which can vary by sample. Parentheses denote uncertainty in the last digits. Half-lives and decay branches use NUBASE2020; # marks estimates, >/< mark limits. “No decay observed” follows that evaluation and does not prove permanent stability. Decay branch intensities are percentages; SF means spontaneous fission, EC electron capture, IT an isomeric transition.
Follow the science
Use these original references to explore the data and context. Atomic weights can vary with isotope composition; values for elements without stable isotopes may describe a representative isotope rather than a standard atomic weight.