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Thulium 69Tm168.934
Discovered in 1879 by P.T. Cleve at Uppsala, Sweden.
[Called after Thule, an ancient name for Scandinavia]
French: thulium
German: Thulium
Italian: tulio
Spanish: tulio
Description: Thulium is a silvery metal, and rarest of all the so-called rare earth group (more correctly termed the lantahnides). It tarnishes in air and reacts with water. Thullium has few uses but some is employed as a radiation source in portable x-ray equipment.
Materials properties
| Density: |
9321 kg/m-3 [293 K] |
| Melting point: |
1818 °K |
| Boiling point: |
2220 °K |
| Molar volume: |
18.12 cm3 |
| Thermal conductivity: |
16.8 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: |
13.3 x 10-6 K-1 |
| Electrical resistivity: |
79 x 10-8 [298 K] Wm |
| Mass magnetic susceptibility: |
+1.90 x 10-6(s) kg-1m3 |
| Young's modulus: |
74.0 GPa |
| Rigidity modulus: |
30.5 GPa |
| Bulk modulus: |
44.5 GPa |
| Poisson's ratio: |
0.213 GPa |
| Radii: |
Tm4+ 87; Tm3+ 94; atomic 175; covalent 156 |
| Electronegativity: |
1.25 (Pauling); 1.11 (Allred); ≤ 3.4 eV (absolute) |
| Effective nuclear charge: |
2.85 (Slater); 8.58 (Clementi); 11.80 (Froese-Fischer) |
| Number of Isotopes (incl. nuclear isomers): |
28 |
| Issotope mass range: |
152 -> 176 |
Biological data
| Biological role: |
None, but acts to stimulate metabolism. |
| Toxicity |
|
| Toxic intake: |
n.a. |
| Lethal intake: |
LD 50 (chloride, oral, mouse) = 4290 mg kg -1 |
| Hazards: |
Thulium is mildly toxic by ingestion.
|
| Level in humans |
|
| Organs: |
n.a. but low |
| Daily dietary intake : |
n.a. |
| Total mass of element in average [70 kg] person: |
n.a. |
Crystal data
| Crystal structure, (cell dimentions / pm), space group |
h.c.p. (a=353.75, c=555.46), P63/mmc |
| X-ray diffraction: mass absorption coefficients (µ/ρ)/cm2g-1: |
CuKα 140 MoKα 80.8 |
| Neutron scattering length, b/10-12cm: |
0.707 |
| Thermal neutron capture cross-section, σa/barns : |
100 |
Geological data
| Mineral |
Formula |
Density |
Hardness |
Crystal apperance |
| Bastnäsite* |
(Ce,La,etc)CO3F |
4.9 |
4 - 4.5 |
hex., vit./greasy yellow |
| Monazite* |
(Ce,La,Nd,Th,etc)PO4 |
5.20 |
5 - 5.5 |
mon., waxy/vit. yellow-brown |
*Although not a major constituent, thulium is present in extractable amounts.
| Chief ore: |
monazite, bastnäsite |
| World production: |
c. 50 tonnes/year |
| Main mining areas: |
USA, Brazi, India, Sri Lanka, Australia |
| Reserves: |
c. 1 x 105 tonnes |
| Specimen: |
available as chips, ingots or powder. Safe. |
| Abundances |
|
| Sun: |
1.8 (relative to H = 1 x 1023) |
| Earth's crust: |
0.48 p.p.m. |
| Seawater: |
|
| Atlantic surface: |
1.3 x 10-7 p.p.m. |
| Atlantic deep: |
1.6 x 10-7 p.p.m. |
| Pacific surface: |
0.7 x 10-7 p.p.m. |
| Pacific deep: |
3.3 x 10-7 p.p.m. |
| Residence time: |
n.a. |
| Classification: |
recycled |
| Oxidation state: |
III |
Other sizes and specifications on request
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