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General
States Energies Oxidation & Electrons Appearance & Characteristics Reactions Compounds Radius Conductivity Abundance & Isotopes |
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High Purity Tantalum (Photo: Tomihahndorf) |
General:
| Name: Tantalum | Symbol: Ta |
| Type: Transition Metal | Atomic weight: 180.947 |
| Density @ 293 K: 16.6 g/cm3 | Atomic volume: 10.90 cm3/mol |
| Discovered: Tantalum was discovered by Anders G. Ekeberg in 1802 and was first isolated in 1820 by Jöns Berzelius. The element name comes from the Greek mythological character Tantalos, father of Niobe. | |
States
| State (s, l, g): solid | |
| Melting point: 3293 K (3020 oC) | Boiling point: 5833 K (5560 oC) |
Energies
| Specific heat capacity: 0.14 J g-1 K-1 | Heat of atomization: 782 kJ mol-1 |
| Heat of fusion: 36.57 kJ mol-1 | Heat of vaporization : 737 kJ mol-1 |
| 1st ionization energy: 761 kJ mol-1 | 2nd ionization energy: 1500 kJ mol-1 |
| 3rd ionization energy: kJ mol-1 | Electron affinity: 31.1 kJ mol-1 |
Oxidation & Electrons
| Shells: 2,8,18,32,11,2 | Electron configuration: [Xe] 4f14 5d3 6s2 |
| Minimum oxidation number: -1 | Maximum oxidation number: 5 |
| Min. common oxidation no.: 0 | Max. common oxidation no.: 5 |
| Electronegativity (Pauling Scale): 1.5 | Polarizability volume: 13.1 Å3 |
Appearance & Characteristics
| Structure: bcc: body-centered cubic | Color: gray |
| Harmful effects: Tantalum is considered to be non-toxic. | Hardness: 6.5 mohs |
| Characteristics: Tantalum is a rare, shiny, gray, dense metal. It is highly ductile and can be drawn into a thin wire. Its chemical properties are very similar to those of niobium. Tantalum is highly corrosion resistant due to the formation of an oxide film. It is an excellent conductor of heat and electricity. The metal has a melting point exceeded only by tungsten and rhenium. Tantalum is one of the five major refractory metals (metals with very high resistance to heat and wear). The other refactory metals are tungsten, molybdenum, rhenium and niobium. | |
| Uses: Tantalum is used in the electronics industry for capacitors and high power resistors. It is also used to make alloys to increase strength, ductility and corrosion resistance. The metal is used in dental and surgical instruments and implants, as it causes no immune response. | |
Reactions
| Reaction with air: none | Reaction with 6 M HCl: none |
| Reaction with 15 M HNO3: none | Reaction with 6 M NaOH: none |
Compounds
| Oxide(s): TaO2, Ta2O5 | Chloride(s): TaCl3, TaCl4, TaCl5 |
| Hydride(s): Ta2H |
Radius
| Atomic radius: 146 pm | Ionic radius (1+ ion): pm |
| Ionic radius (2+ ion): pm | Ionic radius (3+ ion): 86 pm |
| Ionic radius (2- ion): pm | Ionic radius (1- ion): pm |
Conductivity
| Thermal conductivity: 57.5 W m-1 K-1 | Electrical conductivity: 8.1 x 106 S m-1 |
Abundance & Isotopes
| Abundance earth's crust: 1.7 parts per million by weight, 0.2 parts per million by moles | |
| Abundance solar system: parts per billion by weight, parts per billion by moles | |
| Cost, pure: $450 per 100g | |
| Cost, bulk: $8.10 per 100g | |
| Source: Tantalum is not found free in nature but in minerals such as columbite and tantalite. Minerals that contain tantalum often also contain niobium. Commercially, tantalum is extracted by first forming the oxide (Ta2O5). The oxide is then reduced using carbon or hydrogen. | |
| Isotopes: Tantalum has 31 isotopes whose half-lives are known, with mass numbers from 156 to 186. Of these, one is stable, 181Ta. | |
