Cerium Element Properties
Complete reference for Cerium (Ce, element 58): atomic data, electron configuration, isotopes, physical constants, oxidation states, and unit converter.
Cerium
Lanthanide — Period 6, f-block
Atomic Identity
Periodic Table Locator — Lanthanide Series Neighborhood
Cerium (Z=58) is the second lanthanide, directly following lanthanum (Z=57) and preceding praseodymium (Z=59). It belongs to Period 6 and the f-block of the periodic table. Thorium (Z=90) is its actinide congener and shares several properties.
Electron Configuration
Two unpaired electrons (4f¹ & 5d¹)
Key Isotopes of Cerium
| Isotope | Symbol | Protons | Neutrons | Mass (u) | Natural Abundance | Stability |
|---|---|---|---|---|---|---|
| Cerium-136 | ¹³⁶Ce | 58 | 78 | 135.907172 | 0.185% | Stable |
| Cerium-138 | ¹³⁸Ce | 58 | 80 | 137.905991 | 0.251% | Stable |
| Cerium-139 | ¹³⁹Ce | 58 | 81 | 138.906653 | Radioactive |
Unstable
Electron capture, t½ = 137.641 d |
| Cerium-140 | ¹⁴⁰Ce | 58 | 82 | 139.905442 | 88.45% | Stable |
| Cerium-141 | ¹⁴¹Ce | 58 | 83 | 140.908276 | Radioactive |
Unstable
β⁻ decay, t½ = 32.511 d |
| Cerium-142 | ¹⁴²Ce | 58 | 84 | 141.909244 | 11.11% | Stable |
| Cerium-144 | ¹⁴⁴Ce | 58 | 86 | 143.913647 | Radioactive |
Unstable
β⁻ decay, t½ = 284.91 d |
Ce-140 accounts for ~88% of natural cerium and has a magic neutron number (N=82), explaining its exceptional stability. Ce-141 and Ce-144 are fission products important in nuclear reactor monitoring. Ce-139 is used as a radiotracer in medical and industrial applications.
Physical Properties
Chemical Properties
Ground State Quantum Numbers
Oxidation States in Detail
Configuration [Xe] 4f¹. Found in most cerium salts. Ce³⁺ is a mild reducing agent in aqueous solution and is the predominant form under ambient conditions.
Configuration [Xe] (empty 4f). Ce⁴⁺ achieves a xenon-like core — highly stable. CeO₂ and Ce(SO₄)₂ are the main Ce(IV) compounds. Ce⁴⁺ is used as a primary standard oxidant in titrimetric analysis (cerimetry).
No other common lanthanide readily adopts a +4 state under ordinary conditions; this makes cerium redox chemistry uniquely versatile among the rare earths.
Property Unit Converter
Convert common Cerium property values between units. Enter a value and select the conversion.
Common Cerium Compounds
| Compound | Formula | Oxidation State | Key Uses |
|---|---|---|---|
| Cerium(IV) oxide | CeO₂ | Ce⁴⁺ | Catalytic converters, glass polishing, solid oxide fuel cells, UV coatings |
| Cerium(III) chloride | CeCl₃ | Ce³⁺ | Luche reduction reagent in organic synthesis, phosphor precursor |
| Cerium(III) nitrate | Ce(NO₃)₃·6H₂O | Ce³⁺ | Phosphor synthesis, rare earth separation feedstock |
| Cerium(IV) sulfate | Ce(SO₄)₂ | Ce⁴⁺ | Cerimetric titrations (primary standard oxidant), laboratory reagent |
| Cerium(III) carbonate | Ce₂(CO₃)₃ | Ce³⁺ | Intermediate for CeO₂ production, dietary supplement |
| Cerium(III) fluoride | CeF₃ | Ce³⁺ | Optical fluoride crystals, scintillator material, luminescent dopant |
| Mischmetall | ~50% Ce alloy | Ce⁰ | Pyrophoric flint in lighters, steel grain-refiner, hydrogen storage alloys |
| Cerium aluminate | CeAlO₃ / Ce:YAG | Ce³⁺ | LED phosphor (Ce³⁺:YAG converts blue to white light) |
Key Facts About Cerium
Most Abundant Rare Earth
At ~66 ppm in Earth's crust, cerium is the most abundant rare earth element — more common than copper (~50 ppm). It occurs in bastnaesite (CeFCO₃), monazite ((Ce,La,Th)PO₄), and laterite deposits worldwide. China dominates global production with over 60% of supply.
Heart of Catalytic Converters
CeO₂ is an indispensable oxygen-storage material in automotive three-way catalytic converters. Its ability to cycle between Ce³⁺ and Ce⁴⁺ allows it to absorb excess oxygen under lean conditions and release it under rich conditions, maintaining the stoichiometric window needed for simultaneous CO, hydrocarbon, and NOₓ conversion.
Photovoltaic & Solid Oxide Fuel Cells
Doped ceria (Gd₀.₂Ce₀.₈O₁.₉, GDC) is one of the best intermediate-temperature electrolytes for solid oxide fuel cells (SOFCs) operating at 500–700 °C. Its mixed ionic-electronic conductivity arises from Ce⁴⁺/Ce³⁺ cycling under reducing atmospheres, enabling higher efficiency than conventional yttria-stabilized zirconia at lower temperatures.
White LED Phosphor
Ce³⁺-doped yttrium aluminum garnet (Ce:YAG, Y₃Al₅O₁₂:Ce) is the dominant phosphor in commercial white LEDs. A blue InGaN LED chip excites Ce³⁺ ions, which emit a broad yellow band (~550 nm). Mixed with the blue primary, this creates the white light used in most LED lighting and backlights worldwide.
Glass Polishing Abrasive
CeO₂ powder has largely replaced iron oxide (rouge) as the preferred abrasive for polishing optical glass, flat-panel displays, and semiconductor wafers. Its action is partly chemical (Ce⁴⁺ forms transient Ce-O-Si bonds that weaken surface silica) and partly mechanical, yielding scratch-free, angstrom-level smooth surfaces.
Discovered Named After a Dwarf Planet
Cerium was independently discovered in 1803 by Jöns Jacob Berzelius and Wilhelm Hisinger in Sweden, and almost simultaneously by Martin Heinrich Klaproth in Germany. They named it after the recently discovered asteroid Ceres (1801) — making cerium the first element named after a solar system body. It was isolated as a pure metal in 1875.
Summary
Complete reference for Cerium (Ce, element 58): atomic data, electron configuration, isotopes, physical constants, oxidation states, and unit converter.
How it works
- Browse the atomic identity section for symbol, atomic number, and standard atomic weight.
- Check the electron configuration panel for orbital notation including the unusual 4f¹ 5d¹ 6s² filling.
- Review the isotopes table for stable and notable radioactive isotopes with natural abundances.
- Consult the physical and chemical properties panels for melting point, density, ionization energies, and more.
- Use the interactive unit converter to convert cerium property values between common units.
- Explore the periodic table locator to visualize where cerium sits among neighboring lanthanides.
Use cases
- Look up cerium constants for chemistry homework or exams.
- Verify atomic data when writing lab reports or research papers on rare earth elements.
- Reference isotope data for nuclear chemistry or geochronology research.
- Convert melting and boiling points between Celsius, Fahrenheit, and Kelvin.
- Teach or learn lanthanide properties using cerium as the first and most abundant example.
- Confirm electron configuration before writing molecular orbital or bonding diagrams.
- Research cerium compounds for catalysis, glass polishing, or automotive catalytic converter work.
- Quick-reference oxidation states and ionization energies for electrochemistry calculations.