Tantal 73Ta180.948
1802 von A.G. Ekeberg in Uppsala, Schweden, entdeckt.
[Griechisch, Tantalos = Vater von Niobe]
French: tantale
English: tantalum
Italian: tantalio
Spanish: tántalo
Beschreibung: Glänzendes, silberfarbiges Metall, in reinem Zustand weich. Durch Passivierung mit einer Oxidhaut sehr widerstandsfähig gegen Korrosion; wird von HF und geschmolzenen Alkalien angegriffen. Verwendung: Elektronik, Schneidwerkzeuge, chemischer Apparatebau, Chirurgie.
Tantal single crystal properties
| State: |
Single crystal |
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| Crystal structure: |
bcc |
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| Production method: |
Floating zone |
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| Standard size: |
diameter 6-12mm
thickness 1-2mm |
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| Orientation: |
(100), (110) and (111) |
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| Orientation accuracy: |
<2°, <1°, <0.4° or <0.1° |
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| Polishing: |
as cut, one or two sides polished |
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| Roughness of surface: |
<0.03µm |
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| Purity: |
99.99% |
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| Typical analysis (ppm): |
C 3
H < 1
O 9
N < 5
Cu 1.60
Fe 1.80
Ni < 1
Pb 0.30
Si 0.30
Ga, Hf and Ta are below the detection limit
|
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Materials properties
| Density: |
16.6 g/cm3 |
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| Melting point: |
2995.85 °C / 3269 °K |
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| Boiling point: |
5424.85±100 °C / 5698±100 °K |
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| Molar volume: |
10.87 cm3 |
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| Thermal conductivity: |
57.5 [300 K] Wm-1K-1 |
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| Coefficient of linear thermal expansion: |
6.6 x 10-6 K-1 |
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| Electrical resistivity: |
12.45x 10-8 [298 K] Wm |
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| Mass magnetic susceptibility: |
+1.07 x 10-8(s) kg-1m3 |
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| Young's modulus: |
185.7 GPa |
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| Rigidity modulus: |
69.2 GPa |
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| Bulk modulus: |
196.3 GPa |
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| Poisson's ratio: |
0.342 GPa |
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| Radii: |
Ta5+ 64; Ta4+ 68; Ta3+ 72; atomic 143; covalent 13 |
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| Electronegativity: |
1.5 (Pauling); 1.33 (Allred); 4.11 eV (absolute) |
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| Effective nuclear charge: |
3.30 (Slater); 9.53 (Clementi); 13.78 (Froese-Fischer) |
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| Number of Isotopes (incl. nuclear isomers): |
28 |
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| Issotope mass range: |
159 -> 186 |
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| Crystal structure, (cell dimentions / pm), space group |
bcc |
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| X-ray diffraction: mass absorption coefficients: |
CuKα 166 (µ/r) / cm2g-1
MoKα 95.4 (µ/r) / cm2g-1 |
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| Neutron scattering length: |
0.691 b/10-12 cm |
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| Thermal neutron capture cross-section: |
20.6 sa / barns |
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Biological data
| Biological role: |
none |
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| Toxicity |
|
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| Toxic intake: |
moderately poisonous by ingestion |
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| Lethal intake: |
LD50 (chloride, oral, rat)= 1900 mg kg-1 |
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| Hazards: |
There are no cases of industrial poisoning caused by tantalum or its compounds. However, it is an experimental tumorigen. |
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| Level in humans |
|
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| Blood: |
n.a., but low |
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| Bone: |
c. 0.03 p.p.m. |
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| Liver: |
n.a. |
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| Muscle: |
n.a., but low |
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| Daily dietary intake: |
0.001 mg |
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| Total mass of element in average [70 kg] person: |
c. 0.2 mg |
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Geological data
| Mineral | Formula | Density | Hardness | Crystal apperance |
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| Columbite |
(Fe, Mn)(Ta, Nb)2O6 |
a group of |
Ferrotanta |
FeTa2O6 |
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| 7.95 |
6 - 6.5 |
orth., bla |
Manganotan |
(Fe, Mn)(Ta, Nb)2O6 |
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| 6.76 |
6 - 6.5 |
orth., bla |
Microlite |
(Na, Ca)2Ta2O6(O, OH, F) |
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| 6.42 |
5 - 5.5 |
cub., vitr |
Samarskite |
(Y, Ce, U, Fe)3(Nb, Ta, Ti)5O16 |
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| 5.69 |
5 - 6 |
orth., vit |
Chief ore: |
columbite, samarskite |
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| Chief ore: |
columbite, samarskite |
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| World production: |
840 tonnes/year |
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| Main mining areas: |
Australia, Zaire, Brazil, Russia, Norway, Canada, Madagascar; mostly obtained as a by-product of tin extraction. |
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| Reserves: |
n.a. |
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| Specimen: |
available as foil, powder, rod or wire. Safe. |
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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: |
2 p.p.m. |
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| Seawater: |
|
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| Residence time: |
|
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| Classification: |
|
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| Oxidation state: |
V |
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English
