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Tantalum,  73Ta
Tantalum single crystal and 1cm3 cube.jpg
Tantalum
Pronunciation/ˈtæntələm/ (TAN-təl-əm)
Appearancegray blue
Standard atomic weight Ar, std(Ta)180.94788(2)
Tantalum in the periodic table
Hydrogen
Helium
Lithium Beryllium
Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium
Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium
Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium

Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Nb

Ta

Db
hafniumtantalumtungsten
Atomic number (Z)73
Groupgroup 5
Periodperiod 6
Blockd-block
Element category  transition metal
Electron configuration[Xe] 4f14 5d3 6s2
Electrons per shell
2, 8, 18, 32, 11, 2
Physical properties
Phase at STPsolid
Melting point3290 K ​(3017 °C, ​5463 °F)
Boiling point5731 K ​(5458 °C, ​9856 °F)
Density (near r.t.)16.69 g/cm3
when liquid (at m.p.)15 g/cm3
Heat of fusion36.57 kJ/mol
Heat of vaporization753 kJ/mol
Molar heat capacity25.36 J/(mol·K)
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−3, −1, +1, +2, +3, +4, +5 (a mildly acidic oxide)
ElectronegativityPauling scale: 1.5
Ionization energies
  • 1st: 761 kJ/mol
  • 2nd: 1500 kJ/mol

Atomic radiusempirical: 146 pm
Covalent radius170±8 pm
Color lines in a spectral range
Spectral lines of tantalum
Other properties
Natural occurrenceprimordial
Crystal structurebody-centered cubic (bcc)
Body-centered cubic crystal structure for tantalum

α-Ta
Crystal structuretetragonal
Tetragonal crystal structure for tantalum

β-Ta
Speed of sound thin rod3400 m/s (at 20 °C)
Thermal expansion6.3 µm/(m·K) (at 25 °C)
Thermal conductivity57.5 W/(m·K)
Electrical resistivity131 nΩ·m (at 20 °C)
Magnetic orderingparamagnetic
Magnetic susceptibility+154.0·10−6 cm3/mol (293 K)
Young's modulus186 GPa
Shear modulus69 GPa
Bulk modulus200 GPa
Poisson ratio0.34
Mohs hardness6.5
Vickers hardness870–1200 MPa
Brinell hardness440–3430 MPa
CAS Number7440-25-7
History
DiscoveryAnders Gustaf Ekeberg (1802)
Recognized as a distinct element byHeinrich Rose (1844)
Main isotopes of tantalum
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
177Ta syn 56.56 h ε 177Hf
178Ta syn 2.36 h ε 178Hf
179Ta syn 1.82 y ε 179Hf
180Ta syn 8.125 h ε 180Hf
β 180W
180mTa 0.012% stable
181Ta 99.988% stable
182Ta syn 114.43 d β 182W
183Ta syn 5.1 d β 183W

Tantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as tantalium, its name comes from Tantalus, a villain from Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant. It is part of the refractory metals group, which are widely used as minor components in alloys. The chemical inertness of tantalum makes it a valuable substance for laboratory equipment and a substitute for platinum. Its main use today is in tantalum capacitors in electronic equipment such as mobile phones, DVD players, video game systems and computers. Tantalum, always together with the chemically similar niobium, occurs in the mineral groups tantalite, columbite and coltan (a mix of columbite and tantalite, though not recognised as a separate mineral species). Tantalum is considered a technology-critical element.

History