Zirconium << zur KOH nee uhm >> is a grayish-white metal. It is found in nature as the silicate mineral zircon and the oxide mineral baddeleyite.
Zirconium is used to make the cores of nuclear reactors because it resists corrosion and does not readily absorb neutrons. Zircaloy is an important alloy (metal mixture) developed for such nuclear applications as a coating for fuel parts. Baddeleyite can withstand extremely high temperatures. It is used for laboratory crucibles (melting pots for metals) and the linings for furnaces.
Zirconium has the chemical symbol Zr. Its atomic number (number of protons in its nucleus) is 40. Its relative atomic mass is 91.224. An element’s relative atomic mass equals its mass (amount of matter) divided by the mass of carbon 12, the most abundant form of carbon. Zirconium melts at 1857 °C and boils at 4200 °C. At 25 °C, its density is 6.51 grams per cubic centimeter (see Density). Chemists classify zirconium as a transition metal. For information on the position of zirconium on the periodic table, see the article Periodic table.
Martin Heinrich Klaproth, a German chemist, isolated the oxide of zirconium from zircon in 1789. Metallic zirconium was first prepared in 1824 by Jons J. Berzelius, a Swedish chemist.
