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Tantalum




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hafniumtantalumtungsten
Nb

Ta

Db
Appearance
gray blue
General properties
Name, symbol, number tantalum, Ta, 73
Pronunciation /ˈtæntələm/
TAN-təl-əm;
previously /tænˈtæliəm/
tan-TAL-ee-əm
Element category transition metal
Group, period, block 56, d
Standard atomic weight 180.94788 g·mol−1
Electron configuration [Xe] 4f14 5d3 6s2
Electrons per shell 2, 8, 18, 32, 11, 2 (Image)
Physical properties
Phase solid
Density (near r.t.) 16.69 g·cm−3
Liquid density at m.p. 15 g·cm−3
Melting point 3290 K, 3017 °C, 5463 °F
Boiling point 5731 K, 5458 °C, 9856 °F
Heat of fusion 36.57 kJ·mol−1
Heat of vaporization 732.8 kJ·mol−1
Specific heat capacity (25 °C) 25.36 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 3297 3597 3957 4395 4939 5634
Atomic properties
Oxidation states 5, 4, 3, 2, -1 (mildly acidic oxide)
Electronegativity 1.5 (Pauling scale)
Ionization energies 1st: 761 kJ·mol−1
2nd: 1500 kJ·mol−1
Atomic radius 146 pm
Covalent radius 170±8 pm
Miscellanea
Crystal structure body-centered cubic
Crystal structure note α-Ta
Magnetic ordering paramagnetic[1]
Electrical resistivity (20 °C) 131 nΩ·m
Thermal conductivity (300 K) 57.5 W·m−1·K−1
Thermal expansion (25 °C) 6.3 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 3400 m/s
Young's modulus 186 GPa
Shear modulus 69 GPa
Bulk modulus 200 GPa
Poisson ratio 0.34
Mohs hardness 6.5
Vickers hardness 873 MPa
Brinell hardness 800 MPa
CAS registry number 7440-25-7
Most stable isotopes
Main article: Isotopes of tantalum
iso NA half-life DM DE (MeV) DP
177Ta syn 56.56 h ε 1.166 177Hf
178Ta syn 2.36 h ε 1.910 178Hf
179Ta syn 1.82 y ε 0.110 179Hf
180Ta syn 8.125 h ε 0.854 180Hf
β 0.708 180W
180mTa 0.012% >1.2×1015 y ε 0.929 180Hf
β 0.783 180W
IT 0.075 180Ta
α 2.103 176Lu
181Ta 99.988% 181Ta is stable with 108 neutrons
182Ta syn 114.43 d β 1.814 182W
183Ta syn 5.1 d β 1.070 183W
Tantalum in a glass tube

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

  1. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.