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General | |||||||||||||||||||||||||||||||
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Name, Symbol, Number | Tantalum, Ta, 73 | ||||||||||||||||||||||||||||||
Chemical series | Transition metals | ||||||||||||||||||||||||||||||
Group, Period, Block | 5 (VB)[?], 6 , d | ||||||||||||||||||||||||||||||
Density, Hardness | 16650 kg/m3, 6.5 | ||||||||||||||||||||||||||||||
Appearance | gray blue | ||||||||||||||||||||||||||||||
Atomic Properties | |||||||||||||||||||||||||||||||
Atomic weight | 180.9479 amu | ||||||||||||||||||||||||||||||
Atomic radius (calc.) | 145 (200) pm | ||||||||||||||||||||||||||||||
Covalent radius | 138 pm | ||||||||||||||||||||||||||||||
van der Waals radius | no data | ||||||||||||||||||||||||||||||
Electron configuration | [Xe]4f14 5d3 6s2 | ||||||||||||||||||||||||||||||
e- 's per energy level | 2, 8, 18, 32, 11, 2 | ||||||||||||||||||||||||||||||
Oxidation state (Oxide) | 5 (mildly acidic) | ||||||||||||||||||||||||||||||
Crystal structure | Cubic body centered | ||||||||||||||||||||||||||||||
Physical Properties | |||||||||||||||||||||||||||||||
State of matter | solid | ||||||||||||||||||||||||||||||
Melting point | 3290 K (5463 °F) | ||||||||||||||||||||||||||||||
Boiling point | 5731 K (9856 °F) | ||||||||||||||||||||||||||||||
Molar volume | 10.85 ×10-3 m3/mol | ||||||||||||||||||||||||||||||
Heat of vaporization | 743 kJ/mol | ||||||||||||||||||||||||||||||
Heat of fusion | 31.6 kJ/mol | ||||||||||||||||||||||||||||||
Vapor pressure | 0.776 Pa at 3269 K | ||||||||||||||||||||||||||||||
Speed of sound | 3400 m/s at 293.15 K | ||||||||||||||||||||||||||||||
Miscellaneous | |||||||||||||||||||||||||||||||
Electronegativity | 1.5 (Pauling scale) | ||||||||||||||||||||||||||||||
Specific heat capacity | 140 J/(kg*K) | ||||||||||||||||||||||||||||||
Electrical conductivity | 7.61 106/m ohm | ||||||||||||||||||||||||||||||
Thermal conductivity | 57.5 W/(m*K) | ||||||||||||||||||||||||||||||
1st ionization potential | 761 kJ/mol | ||||||||||||||||||||||||||||||
2nd ionization potential | 1500 kJ/mol | ||||||||||||||||||||||||||||||
Most Stable/Notable Isotopes | |||||||||||||||||||||||||||||||
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SI units & STP are used except where noted. |
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Tantalum is also used to produce a variety of alloys that have high melting points, are strong and have good ductility. Alloyed with other metals, it is also used in making carbide tools for metalworking equipment and in the production of superalloys[?] for jet engine components, chemical process equipment, nuclear reactors, and missile parts. It is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals such as aluminum.
Because it is totally immune to the action of body liquids and is nonirritating it is widely used in making surgical appliances. Tantalum oxide is to make special high index of refraction glass for camera lenses. The metal is also used to make vacuum furnace[?] parts.
Its name is derived from the character Tantalus, father of Niobe in Greek mythology, who was punished after death by being condemned to stand knee-deep in water with perfect fruit growing above his head, both of which eternally tantalized him - if he bent to drink the water, it drained below the level he could reach, and if he reached for the fruit, the branches moved out of his grasp. This was considered similar to tantalum's general non-reactivity - it sits among reagents and is unaffected by them.
Tantalum ores are mined in Australia, Brazil, Canada, the Democratic Republic of the Congo, Mozambique, Nigeria, Portugal, and Thailand.
Tantalite is largely found mixed with columbite in an ore called coltan, about whose sources ethical questions have been raised (see the article).
Several complicated steps are involved in the separation of tantalum from niobium. Commercially production of this element can follow one of several different methods which includes; electrolysis of molten potassium fluorotantalate, reduction of potassium fluorotantalate with sodium, or by reacting tantalum carbide with tantalum oxide. Tantalum is also a byproduct from tin extraction.
wikipedia.org dumped 2003-03-17 with terodump