64 Gd Gadolinium 157.25
Lanthanide f-block Period 6

Gadolinium

Gd · Element 64 · Lanthanide

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The rare earth with the greatest neutron capture cross-section of any stable nuclide.

State at 20°C Solid
Atomic mass 157.25 u
Electron configuration[Xe] 4f⁷ 5d¹ 6s²
63Eu All 118 65Tb

Structure

The gadolinium atom

Not a diagram of dots on rings — a Monte-Carlo sample of the actual probability density |ψ|² for each occupied subshell. Drag to rotate. Blue and violet mark opposite signs of the wavefunction, which is what makes bonding possible.

Orbital cloud

Measured values

Property sheet

Every bar shows where gadolinium sits among all 118 elements for that property.

Physical

Density 7.9 g/cm³ 50%
Melting point 1585 K 66%
Boiling point 3546 K 75%
Specific heat 0.236 J/g·K
Thermal conductivity 10.5 W/m·K 28%

Atomic

Atomic radius 178 pm 65%
Covalent radius 196 pm
Van der Waals radius 237 pm

Electronic

Electronegativity 1.2 19%
Ionisation energy 593.4 kJ/mol 30%
Electron affinity —

Occurrence

Abundance in crust 6.2 mg/kg 66%

Identity

SymbolGd
Atomic number64
Atomic mass157.25 u
CategoryLanthanide
Blockf
Crystal structurehexagonal close-packed
Oxidation states+3
Discovered1880
Discovered byJean Charles Galissard de Marignac

Sources: IUPAC 2021 standard atomic weights · CRC Handbook of Chemistry and Physics · NIST. Values marked ~ are predicted rather than measured.

Same element, different neutrons

Isotopes of gadolinium

All gadolinium atoms have the same number of protons, 64, and differ only in their number of neutrons: those variants are its isotopes. The most common, Gd-158, has 94 neutrons and makes up 24.84% of natural gadolinium.

Isotopes of gadolinium found in nature, with their share of the natural element
ISOTOPE Neutrons Natural Abundance Half-life Decay Mode
Gd-152 88 0.20% 1.08 × 10¹⁴ yrs α
Gd-154 90 2.18% Stable —
Gd-155 91 14.80% Stable —
Gd-156 92 20.47% Stable —
Gd-157 93 15.65% Stable —
Gd-158 most common 94 24.84% Stable —
Gd-160 96 21.86% Stable —

The classroom shortcut, rounded atomic mass minus atomic number, gives 93 for gadolinium, but the most common gadolinium atom has 94 neutrons: the atomic mass, 157.25, is an average over all natural isotopes.

Decay modes

α
alpha decay

Data: IAEA Nuclear Data Section, LiveChart of Nuclides, ground-state evaluations, retrieved October 10, 2026. Abundance is the share of atoms in the natural element; a dash means the isotope has no standard natural abundance.

Size, to scale

How big is a gadolinium atom?

Radius 178 pm — that is 0.178 nm, so about 2.81 million of them side by side would span a millimetre.

Thermal range

Solid, liquid, gas — and when

Gadolinium is liquid over a 1961 K window, from 1585 K to 3546 K.

Where it sits

Position in the table

Gadolinium sits in the lanthanide series, printed below the main grid.

Other lanthanides

57La 58Ce 59Pr 60Nd 61Pm 62Sm 63Eu 65Tb 66Dy 67Ho 68Er 69Tm 70Yb 71Lu
All lanthanides

The story

What gadolinium is, and how we found it

The rare earth with the greatest neutron capture cross-section of any stable nuclide.

The discovery of gadolinium

🏛️ Swiss Scientific Achievement

Jean Charles Galissard de Marignac (1880)

Jean Charles Galissard de Marignac, a Swiss chemist, detected gadolinium spectroscopically in gadolinite and cerite and separated its oxide from cerite. His meticulous analytical work revealed spectroscopic evidence of a new rare earth element.

Systematic Mineral Analysis

Marignac subjected gadolinite samples to systematic fractionation procedures, using precipitation and crystallization techniques to separate different rare earth components. His methodical approach gradually concentrated the unknown element.

Spectroscopic Confirmation

Using advanced spectroscopic equipment, Marignac identified characteristic absorption lines that couldn't be attributed to known elements. These spectral signatures provided definitive proof of a new element in the rare earth series.

Independent Verification

Paul-Émile Lecoq de Boisbaudran independently confirmed Marignac's 1880 discovery in 1886, isolating gadolinium from different mineral sources and verifying its unique properties through complementary analytical techniques.

Naming Etymology

Gadolinium was named after gadolinite mineral, which itself honored Finnish chemist Johan Gadolin, a pioneer in rare earth element research. This naming convention reflected the interconnected nature of rare earth element discoveries.

Pure Metal Production

Pure gadolinium metal wasn't successfully isolated until 1935 by distillation methods. The 55-year gap between discovery and isolation highlights the technical challenges of rare earth metal purification.

Commercial Development

Gadolinium remained primarily of academic interest until the 1960s, when nuclear technology development and medical imaging advancement created commercial demand for the element's unique properties.

Scientific Legacy

  • Analytical chemistry methodology advancement
  • Rare earth element separation techniques
  • Spectroscopic analysis refinement
  • Systematic mineral investigation protocols
🎓 Educational Impact: Marignac's discovery methods became standard curriculum in analytical chemistry, training generations of scientists in systematic element identification.

Applications

What gadolinium is used for

🏥 Medical Technology Pioneer

Gadolinium combines unique magnetic properties with essential nuclear characteristics, making it central for modern medical imaging, nuclear technology, and advanced materials science. Its exceptional neutron absorption capacity and paramagnetic behavior drive critical applications across multiple industries.

Magnetic Resonance Imaging (MRI)

Gadolinium-based contrast agents transform medical imaging by enhancing tissue contrast in MRI scans. These agents improve diagnostic accuracy for brain tumors, cardiovascular disease, and inflammatory conditions, enabling earlier detection and better treatment outcomes.

Nuclear Reactor Control Systems

Gadolinium possesses the highest thermal neutron capture cross-section of any element, making it essential for nuclear reactor safety systems. Gadolinium control rods provide precise reactivity control and emergency shutdown capabilities in commercial nuclear power plants.

Advanced Alloy Development

Gadolinium-enhanced alloys improve magnetic properties in permanent magnets, electronic components, and specialized machinery. These alloys maintain magnetic strength at elevated temperatures and resist demagnetization under stress.

Neutron Detection Technology

High-sensitivity neutron detectors incorporate gadolinium-157 for detecting thermal neutrons in nuclear facilities, border security systems, and scientific research equipment. The isotope's neutron capture produces easily detectable gamma rays.

Specialized Glass Applications

Gadolinium oxide-doped glass creates optical components for laser systems, fiber optic communications, and precision instruments. These glasses offer unique refractive properties and thermal stability for demanding applications.

Targeted Cancer Therapy

Experimental gadolinium neutron capture therapy uses the element's neutron absorption properties to treat certain cancers. When neutrons interact with gadolinium-157, the resulting radiation can destroy cancer cells with minimal damage to healthy tissue.

🔬 Medical Innovation: Gadolinium contrast agents have enabled over 50 million MRI procedures annually, dramatically improving diagnostic capabilities for neurological and cardiovascular conditions.

🔧 Engineering Excellence

Medical Imaging Enhancement

Hospital MRI systems routinely use gadolinium contrast agents to improve image quality and diagnostic accuracy. These agents help physicians identify tumors, blood vessel abnormalities, and inflammatory processes that would otherwise remain undetectable.

Nuclear Power Safety

Commercial nuclear reactors incorporate gadolinium control rods and burnable poison assemblies to maintain safe operating conditions. The element's neutron absorption properties provide reliable reactor control throughout the fuel cycle.

Electronic Component Manufacturing

Computer hard drives and magnetic storage devices use gadolinium-enhanced magnetic materials for data storage and retrieval systems. The element's magnetic properties enable higher storage densities and improved data reliability.

Industrial Radiography

Non-destructive testing equipment employs gadolinium neutron converter screens for inspecting welds, castings, and critical components in aerospace, automotive, and construction industries.

Research Laboratory Equipment

Scientific instruments utilize gadolinium in neutron scattering experiments, materials research, and fundamental physics studies. The element's unique nuclear properties enable precise measurements and advanced research capabilities.

Specialty Alloys

High-performance alloys for aerospace applications incorporate gadolinium to improve magnetic properties, corrosion resistance, and high-temperature performance in jet engines and spacecraft components.

🚀 Future Technologies

  • Quantum computing magnetic shielding systems
  • Advanced medical imaging contrast agents
  • Next-generation neutron detection arrays
  • Magnetic refrigeration cooling systems

Where it comes from

Natural occurrence

6.2 mg/kg of Earth's crust · more abundant than 66% of elements

🗻 Global Rare Earth Resources

Mineral Distribution

Gadolinium occurs in rare earth bearing minerals including monazite, bastnäsite, and gadolinite (named, like the element, after chemist Johan Gadolin). The highest concentrations appear in carbonatite complexes and alkaline igneous rocks worldwide.

Major Global Deposits

Significant gadolinium resources include:

  • China: Bayan Obo (Inner Mongolia) - dominant global producer
  • United States: Mountain Pass (California) rare earth mine
  • Australia: Mount Weld project in Western Australia
  • Brazil: Catalão complex in Goiás state
  • India: Kerala monazite beach sand deposits

Geological Formation Processes

Gadolinium concentrates through magmatic differentiation in alkaline igneous systems, where late-stage crystallization processes enrich rare earth elements. Weathering and secondary concentration create additional deposits in some regions.

Abundance and Extraction

With crustal abundance of approximately 6.2 parts per million, gadolinium is more abundant than tin but less common than copper. Commercial extraction requires complex separation processes due to similar chemical properties among lanthanides.

Processing Challenges

Gadolinium purification involves multi-stage ion exchange and solvent extraction procedures. The element's position in the middle of the lanthanide series makes separation particularly challenging and energy-intensive.

Strategic Importance

Critical applications in nuclear and medical technologies make gadolinium supply security strategically important for developed nations. Recycling from electronic waste and developing alternative sources are ongoing priorities.

Environmental Considerations

Rare earth mining often involves radioactive material handling due to thorium and uranium co-occurrence. Modern extraction facilities implement comprehensive environmental protection measures and waste management systems.

💎 Strategic Material: Gadolinium's dual importance for medical and nuclear applications makes it a critical material for national security and public health infrastructure.

Handling

Safety

⚗️ Medical Grade Safety

Low Acute Toxicity

Gadolinium compounds generally exhibit low acute toxicity, but chronic exposure requires careful monitoring. Medical-grade gadolinium contrast agents undergo rigorous safety testing and are considered safe for diagnostic use.

Chelation Chemistry Concerns

Free gadolinium ions can be toxic to biological systems, but chelated forms used in medical applications safely bind the metal. However, traces of gadolinium remain in the brain and other tissues for months to years after a scan, even in people with healthy kidneys, and in patients with severe kidney disease some agents can cause nephrogenic systemic fibrosis, a serious scarring disease, so those agents are avoided.

Personal Protective Equipment

  • Safety glasses and laboratory coats
  • Chemical-resistant gloves (nitrile recommended)
  • Fume hood ventilation for powder handling
  • Dust masks when working with dry compounds

Safe Handling Procedures

Handle gadolinium compounds in well-ventilated areas to prevent inhalation exposure. Avoid generating dust or aerosols, and use appropriate containment for powder manipulation. Maintain good laboratory hygiene practices.

Medical Application Safety

MRI contrast agents require careful patient screening for kidney function and allergic reactions. Healthcare providers must follow established protocols for dosing, administration, and post-procedure monitoring.

Storage Requirements

Store gadolinium compounds in sealed containers in cool, dry locations away from incompatible materials. Maintain proper labeling and inventory control, especially for materials intended for medical use.

Emergency Procedures

Skin contact: Wash thoroughly with soap and water. Eye exposure: Flush with water for 15 minutes and seek medical attention. Ingestion: Do not induce vomiting; seek immediate medical care.

Waste Disposal

Dispose of gadolinium waste according to local hazardous material regulations. Medical facilities must follow specific protocols for contrast agent waste disposal to prevent environmental contamination.

💉 Medical Safety: Gadolinium contrast agents have excellent safety profiles when used appropriately, with serious adverse reactions occurring in less than 0.1% of patients.

Keep exploring

Use gadolinium in the tools

Quick answers

Gadolinium: common questions

What is gadolinium?

Gadolinium (symbol Gd) is element 64 on the periodic table, a lanthanide in period 6. The rare earth with the greatest neutron capture cross-section of any stable nuclide. At room temperature it is a solid.

What is the electron configuration of gadolinium?

Gadolinium's ground-state electron configuration is [Xe] 4f⁷ 5d¹ 6s², giving 6 occupied shells with the distribution 2, 8, 18, 25, 9, 2.

What are the melting and boiling points of gadolinium?

Gadolinium melts at 1585 K (1311.9 °C) and boils at 3546 K (3272.9 °C).

What is the atomic mass of gadolinium?

The standard atomic weight of gadolinium is 157.25 u. That is a weighted average across its naturally occurring isotopes, which is why it is rarely a whole number.

How many neutrons does gadolinium have?

The most common gadolinium atom, Gd-158, has 94 neutrons: its mass number, 158, minus its atomic number, 64. It makes up 24.84% of natural gadolinium. The classroom shortcut, rounded atomic mass (157.25) minus atomic number, gives 93 instead, because the atomic mass is an average over all natural isotopes of gadolinium.

How dense is gadolinium?

Gadolinium has a density of 7.9 g/cm³. Water is 1.0 g/cm³, so a block of gadolinium is about 7.9× heavier.

What is the electronegativity of gadolinium?

Gadolinium has a Pauling electronegativity of 1.2. The scale runs from 0.70 (francium, the least greedy for electrons) to 3.98 (fluorine, the most). A value this low means it readily gives its outer electrons away, forming positive ions.

Who discovered gadolinium, and when?

Gadolinium was discovered in 1880 by Jean Charles Galissard de Marignac. Origin of the name: Johan Gadolin, Finnish chemist.

How common is gadolinium on Earth?

Gadolinium makes up about 6.2 mg/kg of the Earth's crust — uncommon, but not rare.

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