Atomic number:73

Group numbers:5

Period:6

Electronic configuration:[Xe] 4f¹⁴ 5d³ 6s²

Formal oxidation number:+5

Electronegativities:1.5

Atomic radius / pm:143

Relative atomic mass:180.94788 ± 0.00002

 

Tantalum was discovered by Anders Gustaf Ekeberg (SE) in 1802. The origin of the name comes from the Greek word Tantalos meaning father of Niobe in Greek mythology, (tantalum is closely related to niobium in the periodic table). It is a rare, grey, heavy, hard but ductile, metal with a high melting point that reacts with HF and fused alkalis. Metal ignites in air and exposed surfaces form corrosion resistant oxide film. Tantalum is always found with niobium but occurs chiefly in the mineral tantalite. It is often used as an economical substitute for platinum. Tantalum pentoxide is used in capacitors and in camera lenses to increase refracting power. It and its alloys are corrosion and wear resistant so it is used to make surgical and dental tools.

Density / g dm^-3:16654 (293 K)

 15000 (m.p.)

Molar volume / cm³mol^-1:10.87 (293 K)

 12.06 (m.p.)

Electrical resistivity / μΩcm:13.15 (20 °C)

Thermal conductivity / W m^-1K^-1:57.5

Melting point / °C:3017

Boiling point / °C:5458

Heat of fusion / kJ mol^-1:31.4

Heat of vaporization / kJ mol^-1:758.22

Heat of atomization / kJ mol^-1:781.425

1st ionization energy / kJ mol^-1:728.43

2nd ionization energy / kJ mol^-1:-

3rd ionization energy / kJ mol^-1:-

in the atmosphere / ppm:-

in the Earth's crust / ppm:1

in the oceans / ppm:0.0025