PTL:Zirconium
From ChemEd Collaborative
Zirconium is a transition metal in Group IVB and the 5th period. It has oxidation numbers ranging from 0 to +4, with +4 being common. Other elements in Group IVB are titanium (Ti) and hafnium (Hf).
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Discovered
Zircons have been known since biblical times. In 1789 Klaproth analyzed a sample and found a new "earth," ZrO2, which we now call zirconia. An impure sample of the metal was isolated in 1824 by Berzelius, but very pure zirconium was not available until 1914.
Characteristics
Zirconium has an abundance in the earth's crust of about 162 ppm. Of the transition elements only Fe, Ti, and Mn have a greater abundance than Zr.
The metal is hard, shiny, and ductile.
Prepared
It is produced by reducing ZrCl4 with sodium or magnesium (the Kroll process).
ZrCl4 + 4 Na 
4 NaCl + Zr
However, the van Arkel-de Boer process is also useful. Impure Zr is heated in a tube with iodine to form ZrI4, a compound volatile above 200°C. This is passed over a tungsten filament heated to about 1300°C, on which the ZrI4 is decomposed, and pure Zr deposits on the filament.
Reactions
Like the other metals in Group IVB, powdered Zr can ignite spontaneously in the air. In addition, and again like the other metals of the group, it does not react with mineral acids or alkalis. The resistance to corrosion of zirconium is particularly striking.
Uses
Since the element also has a low cross section for neutron absorption (in contrast with Hf), it is ideal (in the form of the allow Zircalloy ®) for use in [cladding the fuel in nuclear reactors]. In fact, 90% of the zirconium produced is used in nuclear reactors. Power reactors may use as much as half-million linear feet of zirconium-containing tubing.
Zirconium is also found in [deodorants] (as an aluminum zirconium salt) and in [percussion caps]. Zirconia, ZrO2, is used in laboratory crucibles that must withstand thermal shock, in the lining of metallurgical furnaces, and in the glass and ceramics industries as a refractory material.
Emission Spectra
This is the emission spectra for Zirconium.
Minerals
The chief minerals of zirconium are zircon (zirconium orthosilicate, ZrSiO4) and baddeleyite (zirconium(IV) oxide, ZrO2). Zircon usually contains about 1.2% hafnium oxide. Some [zircons] are of gem quality.
