Tantalum
Symbol: Ta
Atomic Number: 73
Atomic Mass: 180.9479 amu (atomic mass units)
Melting Point: 2996.0 C (3269.15 K, 5424.8 F)
Boiling Point: 5425.0 C (5698.15 K, 9797.0 F)
Number of Protons: 73
Number of Electrons: 73
Number of Neutrons: 108
Classification: Transition Metal
Crystal Structure: Cubic
Density @ 293 K: 16.654 grams per cubic centimeter
Color: gray/blue
Tantalum was discovered in 1802 by the Swedish chemist Anders Gustaf Ekenberg. The element was discovered in mineral samples from the area of Ytterby in Sweden. Many scientists at the time doubted that is was a new mineral claiming it to be an allotrope of niobium to which it was chemically similar. In 1866 Jean Charles Galissard de Marignac, a Swiss chemist, proved that niobic acid and tantallic acid were different and hence they were formed from two different elements. Tantalum was named after the Greek mythological figure Tantalus who was the father of Niobe in this way the chemical similarities of the two elements were acknowledged. In 1907 the first pure samples of the element were prepared by von Bolton.
This heavy hard mineral is ductile when pure and can be pulled to form a fine wire. Only two elements have higher melting points than tantalum these are tungsten and rhenium. It is resistant to nearly all chemical attacks at room temperature being susceptible only to hydrofluoric acid, acidic solutions containing ionic fluoride and sulphur trioxide.
The most common isotope of the element is tantalum-181. This isotope is stable and makes up 99.988% of the total abundance. The remaining 0.012% is made up of the unstable isotope tantalum-180 which has an extremely long half life. Over forty other unstable isotopes have been produced with half lives ranging from 0.97 milliseconds to1.82 years.
The main mineral sources for tantalum are tantalite, columbite and euxenite. Its high melting point and durability means it has numerous industrial uses.
* Tantalum can be used as a substitute for the more expensive platinum.
* It is used to make components in aircraft and missiles.
* Resistance to chemical attack allows its use in numerous components used in the chemical and nuclear industries.
* As it does not react with any bodily fluids tantalum is used to make surgical instruments.
* It does not set up irritation within the body so is used to make implants such as joint replacements and cranial plates.
* Thin tantalum wire can be used for evaporating metals such as aluminum.
* It is used as an alloying agent with steel to increase melting point, ductility and strength.
* Tantalum pentoxide is dielectric and is used to make capacitors.
* Another use for tantalum pentoxide is in making glass which has a high refractive index and is suitable for high quality camera lenses.
* The composite material made of graphite and tantalum carbide is one of the hardest materials known. It is used to make machine cutting tools.
