Tantalum

Tantalum, ₀₀Ta
Tantalum
Pronunciation	/ˈtæntələm/ (TAN-təl-əm)
Appearance	gray blue
Standard atomic weight Ar°(Ta)
	180.94788(2)
Tantalum in the periodic table
	hafnium ← tantalum → tungsten
Group	group 5
Period	period 6
Block	d-block
Electron configuration	[Xe] 4f14 5d3 6s2
Electrons per shell	2, 8, 18, 32, 11, 2
Physical properties
Phase at STP	solid
Melting point	3290 K (3017 °C, 5463 °F)
Boiling point	5731 K (5458 °C, 9856 °F)
Density (near r.t.)	16.69 g/cm3
when liquid (at m.p.)	15 g/cm3
Heat of fusion	36.57 kJ/mol
Heat of vaporization	753 kJ/mol
Molar heat capacity	25.36 J/(mol·K)
Atomic properties
Oxidation states	−3, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide)
Electronegativity	Pauling scale: 1.5
Ionization energies	1st: 761 kJ/mol ; 2nd: 1500 kJ/mol ; ;
Atomic radius	empirical: 146 pm
Covalent radius	170±8 pm
	Spectral lines of tantalum
Other properties
Natural occurrence	primordial
Crystal structure	body-centered cubic (bcc) ; α-Ta
Crystal structure	tetragonal ; β-Ta
Speed of sound thin rod	3400 m/s (at 20 °C)
Thermal expansion	6.3 µm/(m⋅K) (at 25 °C)
Thermal conductivity	57.5 W/(m⋅K)
Electrical resistivity	131 nΩ⋅m (at 20 °C)
Magnetic ordering	paramagnetic
Molar magnetic susceptibility	+154.0·10−6 cm3/mol (293 K)
Young's modulus	186 GPa
Shear modulus	69 GPa
Bulk modulus	200 GPa
Poisson ratio	0.34
Mohs hardness	6.5
Vickers hardness	870–1200 MPa
Brinell hardness	440–3430 MPa
CAS Number	7440-25-7
History
Discovery	Anders Gustaf Ekeberg (1802)
Recognized as a distinct element by	Heinrich Rose (1844)
Isotopes of tantalum
β−	180W

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.
1 2 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.

[1] "Standard Atomic Weights: Tantalum". CIAAW. 2005.

[crystal_structure-2] 1 2 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.

[magnet-3] 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.

[4] Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

[NUBASE2020-5] 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.

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