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
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| X-ray diffractions mass absorption coefficients: |
CuKa 273 (µ/r) / cm2g-1
MoKa 67.5 (µ/r) / cm2g-1 |
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| Neutron scattering length: |
0.738 b/10-12 cm |
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| Thermal neutron capture cross-section: |
23.4 sa / barns |
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| Density: |
8229 kg/m-3 [293 K] |
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| Melting point: |
1355.85°C / 1629°K |
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| Boiling point: |
3122.85°C / 3396°K |
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| Molar volume: |
19.31 cm3 |
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| Thermal conductivity: |
11.1 [300 K] W m-1K-1 |
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| Coefficient of linear thermal expansion: |
7.0 x 10-6 K-1 |
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| Electrical resistivity: |
114 x 10-8 [295 K] Ωm |
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| Mass magnetic susceptibility: |
+1.15 x 10-5(s) kg-1m3 |
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| Radi: |
Tb4+ 81; Tb3+ 97; atomic 178; covalent 159 |
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| Electronegativity: |
n.a. (Pauling); 1.10 (Allred); ≤ 3.2 eV (absolute) |
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| Effective nuclear charge: |
2.85 (Slater); 8.30 (Clementi); 11.39 (Froese-Fischer) |
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| Number of Isotopes (incl. nuclear isomers): |
31 |
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| Isotope mass range: |
145 -> 165 |
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Biological data
| Biological role: |
None. |
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| Toxicity |
|
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| Toxic intake: |
n.a. |
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| Lethal intake: |
LD50 (chloride, oral, mouse) = >5100 mg Kg-1 |
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| Hazards: |
Terbium is mildly toxic by ingestion, and is a skin and eye irritant. |
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| Level in humans |
|
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| Organs: |
n.a., but low |
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| Daily dietary intake: |
n.a. |
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Total mass of element in average
[70 kg] person: |
n.a., but very low |
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Geological data
| Minerals: | |
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| Mineral | Formula | Density | Hardness | Crystal apperance |
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| 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 |
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| World production: |
c. 10 tonnes/year |
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| Producing areas: |
USA, Brazil, India, Sri Lanka, Australia |
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| Reserves: |
c. 3 x 105 tonnes |
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| Specimen: |
available as chips or ingots. Safe. Terbium powder is very irritating to skin and eyes. Care! |
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| Abundances |
|
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| Sun: |
n.a. (relative to H = 1 x 1012) |
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| Earth's crust: |
1.1 ppm |
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| Seawater |
|
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| Atlantic surface: |
1 x 10-7 ppm |
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| Atlantic deep: |
1.5 x 10-7 ppm |
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| Pacific surface: |
0.8 x 10-7 ppm |
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| Pacific deep: |
2.5 x 10-7 ppm |
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| Residence time: |
n.a. |
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| Classification: |
recycled |
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| Oxidation state: |
III |
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Source: Emsley, J. (1998) The Elements (3rd Edition)
Other sizes and specifications on request
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