2/20/2023 0 Comments Periodic table chemistry zrIt is the principal starting compound for the synthesis of many organometallic complexes of zirconium. It is a key intermediate in the conversion of zirconium oxide to metallic zirconium by the Kroll process. Zirconium(IV) chloride or zirconium tetrachloride (ZrCl 4): It is a white, high-melting solid that hydrolyzes rapidly in humid air.Most of them have half-lives that are less than a day, except 95Zr (64.02 days), 88Zr (63.4 days), and 89Zr (78.41 hours). Many other radioisotopes have been characterized. The second most stable radioisotope is 93Zr, which has a half-life of 1.53 million years. In addition, it has one extremely long-lived radioisotope, 96Zr, with an estimated half-life of more than 3.9x10 20. Naturally occurring zirconium is composed of four stable isotopes: 90Zr, 91Zr, 92Zr, and 94Zr. The oxidation state of zirconium is usually +4, although it may also occur in oxidation states of +3 and +2. (It is much more difficult to ignite the solid metal.) An alloy of zirconium and zinc becomes magnetic at temperatures below 35 K. When finely divided, the metal can spontaneously ignite in air, especially at high temperatures. It is lighter than steel, and its hardness is similar to that of copper. ![]() This metal is grayish-white, lustrous, strong, and exceptionally resistant to corrosion. In addition, it lies in group 4 (former group 4B), between titanium and hafnium, and is closely associated with these two elements. Zirconium is a transition metal that is located in period 5 of the periodic table, between yttrium and niobium. The crystal bar process (or Iodide process), developed by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925, was the first industrial process for the commercial production of pure, ductile, metallic zirconium. Pure zirconium was first prepared in 1914. ![]() The metal was isolated in an impure form by Berzelius, who heated a mixture of potassium and potassium zirconium fluoride in a small decomposition process conducted in an iron tube. He named the new element Zirkonertz (zirconia). The mineral was not known to contain a new element until Klaproth analyzed a jargon from Sri Lanka in the Indian Ocean. The mineral zircon, or its variations (jargon, hyacinth, jacinth, or ligure), can be found in biblical writings. Zirconium (Arabic zarkûn, from Persian zargûn زرگون, meaning "gold like") was discovered in 1789 by Martin Heinrich Klaproth and isolated in 1824 by Jöns Jakob Berzelius. The zirconium is used mostly almost pure, in the form of low alloys, most often from the zircaloy group. The separated hafnium is used for control rods. The resulting reactor-grade zirconium is about ten times as expensive as the hafnium-contaminated commercial grade. Two main processes are used for this purpose: liquid-liquid extraction, used mainly in United States, and extractive distillation, used primarily in Europe. ![]() Nonetheless, for applications in nuclear reactors (see below), zirconium needs to be prepared free of hafnium contamination. Commercial-quality zirconium retains a content of 1–3 percent hafnium.Ĭommercial zirconium naturally contains 1-5 percent of hafnium, and it is extremely difficult to separate these two elements from each other. This metal is commercially produced by reducing zirconium(IV) chloride with magnesium in the Kroll process, and by other methods. Zirconium is also in 30 other recognized mineral species including baddeleyite. Zircon is a co-product or byproduct of the mining and processing of heavy mineral sands for certain minerals of titanium (ilmenite and rutile) and tin. Lunar rock samples brought back from several Apollo program missions to the Moon have a high content of zirconium oxide relative to that in terrestrial rocks. This element is also abundant in S-type stars and has been detected in the Sun and meteorites. Zirconium and hafnium are contained in zircon at a ratio of about 50 to 1 and are difficult to separate. Upon extraction, it appears as a dark, sooty powder, or a gray, metallic, crystalline substance. The principal economic source of zirconium is the mineral zircon (zirconium silicate, ZrSiO 4), deposits of which are located in Australia, Brazil, India, Russia, and the United States. In nature, zirconium is found combined with other elements but has never been found as a free metal. It is obtained chiefly from the silicate mineral zircon and is highly resistant to corrosion. Zirconium (chemical symbol Zr, atomic number 40) is a strong, lustrous, gray-white metal that resembles titanium.
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