Terbium

Terbium (Tb)

Silvery metallic element belonging to the lanthanoids. Tb-159 is the only stable isotope, there are seventeen artificial isotopes. Discovered by G.G. Mosander in 1843.
Atomic Number65
Atomic Weight158.92535
Mass Number159
Group
Period6
Blockf
Protons65 p+
Neutrons94 n0
Electrons65 e-
Terbium element.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
175 pm
Atomic Volume
Covalent Radius
168 pm
Metallic Radius
Ionic Radius
92.3 pm
Crystal Radius
106.3 pm
Van der Waals radius
233 pm
Density
8.23 g/cm³
Boiling Point
3,296 K
Melting Point
1,629 K
Electrons per shell2, 8, 18, 27, 8, 2
Electronegativity
Electrophilicity
1.3142725121308 eV/particle
Proton Affinity
Electron Affinity
Ionization Potential
Heat of Vaporization
389 kJ/mol
Heat of Fusion
Heat of Formation
388.7 kJ/mol
Molar Heat Capacity
28.91 J/(mol K)
Specific Heat Capacity
0.182 J/(g⋅K)
Thermal Conductivity
11.1 W/(m K)
Gas Basicity
Dipole Polarizability
170 a₀
C6 Dispersion Coefficient
Oxidation States1, 3, 4
Color
Silver
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
3.6 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Xe] 4f9 6s2
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
Poisson Ratio
Shear Modulus
Young's Modulus
Allotropes
Alternate Names
Adiabatic Index
Appearance
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Electrical
Hardness
Magnetic Susceptibility
Magnetic
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
Classification
CategoryLanthanides, Lanthanides
CAS Group
IUPAC Group
Glawe Number25
Mendeleev Number29
Pettifor Number26
Geochemical Classrare earth & related
Goldschmidt Classlitophile
Radioactivity
RadioactiveNo
Decay Mode
Half-Life
Lifetime
Abundance
Abundance in Earth's crust
1.2 mg/kg
Abundance in Oceans
0.00000014 mg/L
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe5×10-8%

Isotopes of Terbium

Stable Isotopes
159Tb
Unstable Isotopes
136Tb 137Tb 138Tb 139Tb 140Tb 141Tb 142Tb 143Tb 144Tb 145Tb 146Tb 147Tb 148Tb 149Tb 150Tb 151Tb 152Tb 153Tb 154Tb 155Tb 156Tb 157Tb 158Tb 160Tb 161Tb 162Tb 163Tb 164Tb 165Tb 166Tb 167Tb 168Tb 169Tb 170Tb 171Tb

History

Terbium was discovered in 1843 by Swedish chemist Carl Gustaf Mosander, who detected it as an impurity in yttria. Using ammonium hydroxide he precipitated fractions of different basicity from yttria. In these fractions he found that the fraction that was essentially colorless in solution, but gave a brown-tinged oxide was terbium. Terbium was named after Ytterby, a town in Sweden

DiscoverersCarl Mosander
Discovery LocationSweden
Discovery Year1843
Name OriginNamed after Ytterby, a village in Sweden.
Terbium is considered to be moderately toxic
Terbium is soft enough to be cut with a knife

Uses

Terbium is used in alloys and in the production of electronic devices. It is also used as a dopant for materials in solid-state devices and optical fibers. Terbium oxide is in fluorescent lamps and TV tubes. The brilliant fluorescence allows terbium to be used as a probe in biochemistry. It is used in modest amounts in special lasers and solid-state devices.

Sources

Found with other rare earths in monazite sand, which typically contain 0.03% terbium. Other sources are xenotime and euxenite, both of which are oxide mixtures that can contain up to 1% terbium.