Atomic Number: 40
Atomic Weight: 91.224
Discovery: Martin Klaproth 1789 (Germany); zircon mineral is mentioned in biblical texts.
Electron Configuration: [Kr] 4d2 5s2
Word Origin: Named for the mineral zircon. Persian zargun: gold-like, which describes the color of the gemstone known as zircon, jargon, hyacinth, jacinth, or ligure.
Isotopes: Natural zirconium consists of 5 isotopes; 15 additional isotopes have been characterized.
Properties: Zirconium is a lustrous grayish-white metal. Finely-divided metal may ignite spontaneously in air, especially at elevated temperatures, but the solid metal is relatively stable. Hafnium is found in zirconium ores and is difficult to separate from zirconium. Commercial-grade zirconium contains from 1% to 3% hafnium. Reactor-grade zirconium is essentially free of hafnium.
Uses: Zircaloy(R) is an important alloy for nuclear applications. Zirconium has a low absorption cross section for neutrons, and is therefore used for nuclear energy applications, such as for cladding fuel elements. Zirconium is exceptionally resistant to corrosion by seawater and many common acids and alkalis, so it is used extensively by the chemical industry where corrosive agents are employed. Zirconium is used as an alloying agent in steel, a getter in vacuum tubes, and as a component in surgical appliances, photoflash bulbs, explosive primers, rayon spinnerets, lamp filaments, etc. Zirconium carbonate is used in poison ivy lotions to combine with urushiol. Zirconium alloyed with zinc becomes magnetic at temperatures below 35°K. Zirconium with niobium is used to make low temperature superconductive magnets. Zirconium oxide (zircon) has a high index of refraction and is used as a gemstone. The impure oxide, zirconia, is used for laboratory crucibles that will withstand heat shock, for furnace linings, and by the glass and ceramic industries as a refractory material.
Element Classification: Transition Metal
Density (g/cc): 6.506
Melting Point (K): 2125
Boiling Point (K): 4650
Appearance: grayish-white, lustrous, corrosion-resistant metal
Atomic Radius (pm): 160
Atomic Volume (cc/mol): 14.1
Covalent Radius (pm): 145
Ionic Radius: 79 (+4e)
Specific Heat (@20°C J/g mol): 0.281
Fusion Heat (kJ/mol): 19.2
Evaporation Heat (kJ/mol): 567
Debye Temperature (K): 250.00
Pauling Negativity Number: 1.33
First Ionizing Energy (kJ/mol): 659.7
Oxidation States: 4
Lattice Structure: Hexagonal
Lattice Constant (Å): 3.230
Lattice C/A Ratio: 1.593
References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)
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