CAS Number7440-58-6
PubChem CID23986
Atomic Radius159
Atomic Volume13.6
Atomic Weight178.49
Boiling Point4,603
Bulk Modulus
CategoryTransition metals
Crystal StructureSimple Hexagonal
Covalent Radius175
Electrical Resistivity
Electron Configuration[Xe] 4f14 5d2 6s2
Electrons per shell2, 8, 18, 32, 10, 2
Heat of Fusion25.5
Heat of Vaporization630
Ionization Potential6.825
Magnetic Ordering
Magnetic Susceptibility
Mass Number72
Melting Point2,233
Atomic Number178
Oxidation States2, 3, 4
Poisson Ratio
Shear Modulus
Specific Heat Capacity0.144
Thermal Conductivity0.23
Van der Waals radius
Young's Modulus
Abundance in Earth's crust0.00033%
Abundance in Universe7×10-8%
Hf Hafnium 72 178.49 4 6 d 72 2227.0 4600.0 [Xe] 4f14 5d2 6s2 2 8 18 32 10 2 13.3 0.00033% Gray Hexagonal 1.3 1.16 {"1":"658.5","2":"1440","3":"2250","4":"3216"} 659 0 4 1.67 13.6 21.76 661.07 0.14 23.0 0 Solid, Conductor, TransitionMetal, Metal, Stable, Natural HAF-ni-em Silvery, ductile metal. Used in reactor control rods because of its ability to absorb neutrons. Obtained from mineral zircon or baddeleyite. egw79BA_0PA Hafnium
Jöns Jakob Berzelius and Wilhelm Hisinger discovered the element in ceria in 1803 in Sweden.

Klaproth discovered it simultaneously and independently in some tantalum samples in Germany.

Carl Gustaf Mosander, who worked closely with Berzelius, prepared metallic cerium in 1825. Cerium was named for the asteroid Ceres 72 1923 Dirk Coster and George Charles von Hevesy Denmark From the Latin name "Hafnia" meaning "Copenhagen"

Isotopes of Cerium

Standard Atomic Weight


Stable Isotopes

174Hf 176Hf 177Hf 178Hf 179Hf 180Hf

Unstable Isotopes

153Hf 154Hf 155Hf 156Hf 157Hf 158Hf 159Hf 160Hf 161Hf 162Hf 163Hf 164Hf 165Hf 166Hf 167Hf 168Hf 169Hf 170Hf 171Hf 172Hf 173Hf 175Hf 181Hf 182Hf 183Hf 184Hf 185Hf 186Hf 187Hf 188Hf

Cerium is considered to be moderately toxic
Seawater contains 1.5 parts per trillion of cerium
Cerium is used in carbon-arc lighting, especially in the motion picture industry.

Cerium oxide is an important component of glass polishing powders and phosphors used in screens and fluorescent lamps.

Cerium compounds are also used in the manufacture of glass, both as a component and as a decolorizer.