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73. TantalumName: Tantalum
Tantalum is a greyish silver, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which can be used as a filament for evaporating metals such as aluminium. Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulphur trioxide. The element has a melting point exceeded only by tungsten and rhenium. Tantalum (Greek Tantalos, mythological character) was discovered in Sweden in 1802 by Anders Ekeberg and isolated in 1820 by Jons Berzelius. Many contemporary chemists believed niobium and tantalum were the same elements until 1844 and later 1866 when researchers showed that niobic and tantalic acids were different compounds. Early investigators were only able to isolate impure metal and the first relatively pure ductile metal was produced by Werner von Bolton in 1903. Wires made with tantalum metal were used for light bulbs until tungsten replaced it. 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. Compounds containing Tantalum are rarely encountered, and the metal does not normally cause problems in the laboratory, but it should still be regarded as highly toxic. There is some evidence that tantalum compounds can cause tumors, and its metal dust is a fire and explosion hazard. Quick links
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