Template:Infobox tantalum

Tantalum,  ₇₃Ta

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General properties
Pronunciation	Template:Infobox element/pronunciation
Appearance	gray blue
Standard atomic weight (Ar, standard)	Template:Infobox element/standard atomic weight
Mass number	Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope)
Tantalum in the periodic table
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Atomic number (Z)	73
Group	Template:Infobox element/group
Period	period 6
Block	d-block
Element category	Template:Infobox element/category format
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
[[Enthalpy of vaporization|Heat of Template:Engvar]]	753 kJ/mol
Molar heat capacity	25.36 J/(mol·K)
[[Vapor pressure|Template:Engvar pressure]] Template:Infobox element/vapor pressure table
Atomic properties
Oxidation states	Template:Infobox element/symbol-to-oxidation-state
Electronegativity	Pauling scale: 1.5
[[Ionization energy|Template:Engvar energies]]	1st: 761 kJ/mol 2nd: 1500 kJ/mol
Atomic radius	empirical: 146 pm
Covalent radius	170±8 pm
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Other properties
Crystal structure	​Template:Infobox element/crystal structure Template:Infobox element/crystal structure α-Ta
Crystal structure	​Template:Infobox element/crystal structure Template:Infobox element/crystal structure 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
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)
Main isotopes of tantalum
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