Terbium (Tb)

We are a leading manufacturer and supplier of research materials

Terbium 65Tb158.92

Discovered in 1843 by C. G. Mosander at Stockholm, Sweden.

[Named after Ytterby, Sweden]

French: terbium
German: Terbium
Italian: terbio
Spanish: terbio

Description: Terbium is a silvery metal, and a particularly rare member of the so-called rare earth group (more correctly termed the lanthanides). It is slowly oxidised by air and reacts with cold water. Terbium is used in solid state devices and lasers.


Further Materials properties


Crystal structure:

(cell dimensions/pm), space group, 
Tb orthorhombic (a=359.0, b=626.0, c=571.5) Cmcm
α-Tb h.c.p. (a=360.10, c=569.36) P63/mmc
β-Tb b.c.c. (a=402) Im3m
T (α -> orthorhombic) = 220 K, T (α -> β) = 1590 K

X-ray diffractions mass absorption coefficients: CuKa 273 (µ/r) / cm2g-1
MoKa 67.5 (µ/r) / cm2g-1
Neutron scattering length: 0.738 b/10-12 cm
Thermal neutron capture cross-section: 23.4 sa / barns
Density: 8229 kg/m-3 [293 K]
Melting point: 1355.85°C / 1629°K
Boiling point: 3122.85°C / 3396°K
Molar volume: 19.31 cm3
Thermal conductivity: 11.1 [300 K] W m-1K-1
Coefficient of linear thermal expansion: 7.0 x 10-6 K-1
Electrical resistivity: 114 x 10-8 [295 K] Ωm
Mass magnetic susceptibility: +1.15 x 10-5(s) kg-1m3
Radi: Tb4+ 81Tb3+ 97; atomic 178; covalent 159
Electronegativity: n.a. (Pauling); 1.10 (Allred); ≤ 3.2 eV (absolute)
Effective nuclear charge: 2.85 (Slater); 8.30 (Clementi); 11.39 (Froese-Fischer)
Number of Isotopes (incl. nuclear isomers): 31
Isotope mass range: 145 -> 165



Biological data


Biological role: None.
Toxic intake: n.a.
Lethal intake: LD50 (chloride, oral, mouse) = >5100 mg Kg-1
Hazards: Terbium is mildly toxic by ingestion, and is a skin and eye irritant.
Level in humans
Organs: n.a., but low 
Daily dietary intake: n.a.
Total mass of element in average
[70 kg] person:

n.a., but very low 

Geological data


MineralFormulaDensityHardnessCrystal apperance
Monazite*  (Ce, La, Nd, Th, etc.)PO4 5.20  5 - 5.5  mon., waxy/vit. yellow-brown

* Although not a major constituent, terbium is present in extractable amounts.

Chief ores:  monazite
World production:  c. 10 tonnes/year
Producing areas:  USA, Brazil, India, Sri Lanka, Australia
Reserves:  c. 3 x 10tonnes
Specimen:  available as chips or ingots. Safe. Terbium powder is very irritating to skin and eyes. Care!


Sun: n.a. (relative to H = 1 x 1012)
Earth's crust: 1.1 ppm
Atlantic surface: 1 x 10-7 ppm
Atlantic deep: 1.5 x 10-7 ppm
Pacific surface: 0.8 x 10-7 ppm
Pacific deep: 2.5 x 10-7 ppm
Residence time: n.a.
Classification: recycled
Oxidation state: III

  Source: Emsley, J. (1998) The Elements (3rd Edition)

Other sizes and specifications on request

Overview of elements with access to our shop

1 18
2 13 14 15 16 17
Li Be B C
Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se
Rb Sr Y Zr Nb Mo
Ru Rh Pd Ag Cd In Sn Sb Te I
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi
Ce Pr Nd
Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Get our latest news and special sales
You may unsubscribe at any moment. For that purpose, please find our contact info in the legal notice.
Tel.: +49 (0) 2461 - 9352 - 0
Fax: +49 (0) 2461 - 9352 - 11