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Tantalum is a chemical element; it has symbol Ta and atomic number 73. Previously known as tantalium, [citation needed] it is named after Tantalus, a figure in Greek mythology. [11] Tantalum is a very hard, ductile, lustrous, blue-gray transition metal that is highly corrosion-resistant.
Tantalum halides span the oxidation states of +5, +4, and +3. Tantalum pentafluoride (TaF 5) is a white solid with a melting point of 97.0 °C. The anion [TaF 7] 2-is used for its separation from niobium. [55] The chloride TaCl 5, which exists as a dimer, is the main reagent in synthesis of new Ta compounds. It hydrolyzes readily to an oxychloride.
Tantalum ores often contain significant amounts of niobium, which is itself a valuable metal.As such, both metals are extracted so that they may be sold. The overall process is one of hydrometallurgy and begins with a leaching step; in which the ore is treated with hydrofluoric acid and sulfuric acid to produce water-soluble hydrogen fluorides, such as the heptafluorotantalate.
Tantalum pentachloride can be prepared by reacting powdered metallic tantalum with chlorine gas at between 170 and 250 °C. This reaction can also be performed using HCl at 400 °C. [4] 2 Ta + 5 Cl 2 → 2 TaCl 5 2 Ta + 10 HCl → 2 TaCl 5 + 5 H 2. It can also be prepared by a reaction between tantalum pentoxide and thionyl chloride at 240 °C
With the addition of squarate or perchlorate, the tantalum complex dimerises in acetonitrile, with their respective chelating ligands bridging the Ta centres. These seven-coordinate complexes of the form TaMe 3 L 2 , where L is a bidentate monoanion, are markedly more thermally stable than their precursor, decomposing in the range 80 - 120°C.
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Lead scandium tantalate (PST) is a mixed oxide of lead, scandium, and tantalum.It has the formula Pb(Sc 0.5 Ta 0.5)O 3.It is a ceramic material with a perovskite structure, [1] where the Sc and Ta atoms at the B site have an arrangement that is intermediate between ordered and disordered configurations, and can be fine-tuned with thermal treatment. [2]
European Union governments cannot pick and choose whether to execute arrest warrants issued by the International Criminal Court against two Israeli leaders and a Hamas commander, the EU's foreign ...