The Element Tantalum
[Click for Isotope Data]
Atomic Number: 73
Atomic Weight: 180.94788
Melting Point: 3290 K (3017°C or 5463°F)
Boiling Point: 5731 K (5458°C or 9856°F)
Density: 16.4 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 6 Group Number: 5 Group Name: none
What's in a name? Named for the Greek mythological figure Tantalus.
Say what? Tantalum is pronounced as TAN-te-lem.
History and Uses:
Tantalum was discovered by Anders Gustaf Ekenberg, a Swedish chemist, in 1802 in minerals obtained from Ytterby, Sweden. Many scientists believed that he had only discovered an allotrope of niobium, an element that is chemically similar to tantalum. The issue was finally settled in 1866 when, Jean Charles Galissard de Marignac, a Swiss chemist, proved that tantalum and niobium were two distinct elements. The first relatively pure samples of tantalum were first produced in 1907. Today, tantalum is primarily obtained from the minerals columbite ((Fe, Mn, Mg)(Nb, Ta)2O6), tantalite ((Fe, Mn)(Ta, Nb)2O6) and euxenite ((Y, Ca, Er, La, Ce, U, Th)(Nb, Ta, Ti)2O6).
Tantalum is a strong, ductile metal that is nearly immune to chemical attack at room temperatures. It can be drawn into a fine wire that is used to evaporate metals, such as aluminum. It has a high melting point and is frequently used as a substitute for platinum, which is more expensive. Tantalum is used to make components for chemical plants, nuclear power plants, airplanes and missiles. Tantalum does not react with bodily fluids and is used to make surgical equipment. Tantalum also does not irritate the body and is used to make surgical sutures as well as implants, such as artificial joints and cranial plates. Tantalum is alloyed with steel to increase steel's ductility, strength and melting point.
Tantalum pentoxide (Ta2O5), one of tantalum's compounds, is a dielectric material and is used to make capacitors. It is also used to make a glass with a high index of refraction that is used in camera lenses. A composite consisting of tantalum carbide (TaC) and graphite is one of the hardest materials known and is used on the cutting edges of high-speed machine tools.
Estimated Crustal Abundance: 2.0 milligrams per kilogram
Estimated Oceanic Abundance: 2×10-6 milligrams per liter
Number of Stable Isotopes: 1 (View all isotope data)
Ionization Energy: 7.89 eV
Oxidation States: +5
3s2 3p6 3d10
4s2 4p6 4d10 4f14
5s2 5p6 5d3