Tantalum, 00Ta |
|
| Pronunciation | (TAN-təl-əm) |
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| Appearance | gray blue |
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|
|
| 180.94788(2)[1] |
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|
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| Group | group 5 |
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| Period | period 6 |
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| Block | d-block |
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| Electron configuration | [Xe] 4f14 5d3 6s2 |
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| Electrons per shell | 2, 8, 18, 32, 11, 2 |
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|
| Phase at STP | solid |
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| Melting point | 3290 K (3017 °C, 5463 °F) |
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| Boiling point | 5731 K (5458 °C, 9856 °F) |
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| Density (near r.t.) | 16.69 g/cm3 |
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| when liquid (at m.p.) | 15 g/cm3 |
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| Heat of fusion | 36.57 kJ/mol |
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| Heat of vaporization | 753 kJ/mol |
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| Molar heat capacity | 25.36 J/(mol·K) |
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Vapor pressure
| P (Pa)
|
1
|
10
|
100
|
1 k
|
10 k
|
100 k
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| at T (K)
|
3297
|
3597
|
3957
|
4395
|
4939
|
5634
|
|
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| Oxidation states | −3, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide) |
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| Electronegativity | Pauling scale: 1.5 |
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| Ionization energies | - 1st: 761 kJ/mol
- 2nd: 1500 kJ/mol
-
|
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| Atomic radius | empirical: 146 pm |
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| Covalent radius | 170±8 pm |
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| Spectral lines of tantalum |
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| Natural occurrence | primordial |
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| Crystal structure | body-centered cubic (bcc)[2]
α-Ta |
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| Crystal structure | tetragonal[2]
β-Ta |
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| Speed of sound thin rod | 3400 m/s (at 20 °C) |
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| Thermal expansion | 6.3 µm/(m⋅K) (at 25 °C) |
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| Thermal conductivity | 57.5 W/(m⋅K) |
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| Electrical resistivity | 131 nΩ⋅m (at 20 °C) |
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| Magnetic ordering | paramagnetic[3] |
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| Molar magnetic susceptibility | +154.0·10−6 cm3/mol (293 K)[4] |
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| Young's modulus | 186 GPa |
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| Shear modulus | 69 GPa |
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| Bulk modulus | 200 GPa |
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| Poisson ratio | 0.34 |
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| Mohs hardness | 6.5 |
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| Vickers hardness | 870–1200 MPa |
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| Brinell hardness | 440–3430 MPa |
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| CAS Number | 7440-25-7 |
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|
| Discovery | Anders Gustaf Ekeberg (1802) |
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| Recognized as a distinct element by | Heinrich Rose (1844) |
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|
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| Main isotopes[5]
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Decay
|
|
|
abundance
|
half-life (t1/2)
|
mode
|
product
|
| 177Ta
|
synth
|
56.56 h
|
β+
|
177Hf
|
| 178Ta
|
synth
|
2.36 h
|
β+
|
178Hf
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| 179Ta
|
synth
|
1.82 y
|
ε
|
179Hf
|
| 180Ta
|
synth
|
8.125 h
|
ε
|
180Hf
|
| β−
|
180W
|
| 180mTa
|
0.0120%
|
stable
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| 181Ta
|
99.988%
|
stable
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| 182Ta
|
synth
|
114.43 d
|
β−
|
182W
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| 183Ta
|
synth
|
5.1 d
|
β−
|
183W
| |
|
|
|
Tantalum is a chemical element. Tantalum was named tantalium. It has the chemical symbol Ta. It has the atomic number 73. It is a rare metal. It is hard and blue-gray. In chemistry it is placed in a group of metal elements named the transition metals.
Tantalum does not easily corrode. It is found in the mineral tantalite.
Sources
- ↑ "Standard Atomic Weights: Tantalum". CIAAW. 2005.
- ↑ 2.0 2.1 Moseley, P. T.; Seabrook, C. J. (1973). "The crystal structure of β-tantalum". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 29 (5): 1170–1171. doi:10.1107/S0567740873004140.
- ↑ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
- ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
- ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.