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[change | edit source]

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