Zirconium

= = Zirconium


 * Atomic number: 40**
 * Atomic __Weight__:** 91.224
 * Melting Point:** 2128 K (1855°C or 3371°F)
 * Boiling Point:** 4682 K (4409°C or 7968°F)
 * Density:** 6.52 grams per cubic centimeter
 * Phase at Room Temperature:** Solid
 * Element Classification:** Metal
 * Period Number:** 5 **Group Number:** 4


 * =====Zirconium is from the Persian word for gold-like, Zargun.=====
 * [[image:http://nobel.scas.bcit.ca/resource/ptable/ptblegif/zr.gif align="right"]]Zirconium is a gray white transition metal that resembles titanium. It is very soft ductile and malleable. It is a solid at room temperature.

Zirconium reacts with the [|oxygen] and [|nitrogen] in the atmosphere to form a protective film that prevents further corrosion of the metal. It is known in industry as a tough, corrosion-resistant metal that is suitable for use in high-performance pumps, valves, and building material for jets and rockets. Zirconium has very low neutron absorption capability and it serves as the inner lining of reactors in nuclear submarines and atomic power plants. Its compounds have many miscellaneous __applications__ in ceramics, [|catalysts], and __special__ alloys. When alloyed with [|niobium], zirconium becomes [|superconductive]. The sulfate of zirconium is used in tanning __white leather__.

**Characteristics of Zirconium:**
Zirconium is a lustrous, grayish-white, soft, ductile and malleable metal which is solid at room temperature, though it becomes hard and brittle at lower purities. In powder form, zirconium is highly flammable, but the solid form is far less prone to ignition. Zirconium is highly resistant to corrosion by alkalis, acids, salt water and other agents. However, it will dissolve in hydrochloric and sulfuric acid, especially when fluorine is present. Alloys with zinc become magnetic below 35 K. Zirconium's melting point is 1855 °C (3371 °F), and its boiling point is 4371 °C (7900 °F). Zirconium has an electronegativity of 1.33 on the Pauling scale. Of the elements within d-block, zirconium has the fourth lowest electronegativity after yttrium, lutetium and hafnium.

__**History and Uses:**__ Zirconium was discovered by Martin Heinrich Klaproth, a German chemist, while analyzing the composition of the mineral jargon (ZrSiO 4 ) in 1789. Zirconium was isolated by Jöns Jacob Berzelius, a Swedish chemist, in 1824 and finally prepared in a pure form in 1914. Obtaining pure zirconium is very difficult because it is chemically similar to [|hafnium], an element which is always found mixed with deposits of zirconium. Today, most zirconium is obtained from the minerals __zircon__ (ZrSiO 4 ) and baddeleyite (ZrO 2 ) through a process known as the Kroll Process. Zirconium is a corrosion resistant metal that is used in high performance pumps and valves. Since it also does not easily absorb [|neutrons], zirconium is widely used in nuclear reactors. The nuclear power industry uses nearly 90% of the zirconium produced each year, which must be nearly free of hafnium. Zirconium is also used as an alloying agent in steel, to make some types of surgical equipment and as a getter, a material that combines with and removes trace gases from vacuum tubes. Zircon (ZrSiO4) is a zirconium compound that can take many different forms, the most popular of which is a clear, transparent gemstone that can be cut to look like diamond and is frequently used in jewelry. Zirconium dioxide (ZrO 2 ) can withstand very high temperatures and is used to make crucibles and to line the walls of high temperature __furnaces__. Zirconium carbonate (3ZrO 2 ·CO 2 ·H 2 O) is used in lotions to treat poison ivy. The metal is used in the nuclear industry for cladding fuel elements since it has a low absorption cross section for neutrons. Zirconium is very resistant to corrosion by many common acids and alkalis and by sea water. It is therefore used extensively by the chemical industry where corrosive agents are employed. The metal is used as an alloying agent in steel and for making surgical appliances. The metal superconducts at low temperatures and zirconium/niobium alloys are used to make superconductor magnets. Alloys with zinc become magnetic at temperatures below 35 K. Zirconium is used as a "getter" in vacuum tubes, in flash bulbs for photography, in explosive primers, and in lamp filaments. The oxide (zircon) has a high index of refraction and is a good gem material. The oxide is also used for laboratory crucibles that will withstand heat shock, for linings of metallurgical furnaces, and by the glass and ceramic industries as a refractory material.

Zirconium has a concentration of about 130 mg/kg within the earth's crust and about 0.026 μg/L in sea water. It is not found in nature as a native metal, reflecting its intrinsic instability with respect to water. The principal commercial source of zirconium is the silicate mineral, zircon (ZrSiO 4 ), which is found primarily in Australia, Brazil, India, Russia, South Africa and the United States, as well as in smaller deposits around the world. 80% of zircon mining occurs in Australia and South Africa. Zircon resources exceed 60 million metric tons worldwide and annual worldwide zirconium production is approximately 900,000 metric tons. Zirconium also occurs in more than 140 other minerals, including the commercially useful ores baddeleyite and kosnarite. Zr is relatively abundant in S-type stars, and it has been detected in the sun and in meteorites. Lunar rock samples brought back from several Apollo program missions to the moon have a quite high zirconium oxide content relative to terrestrial rocks.
 * Occurrences:**

Sources: []

Harmful effects: Zirconium is considered to be non-toxic.. Characteristics: Zirconium is a strong, malleable, ductile, lustrous, grayish-white metal. It is generally exceptionally resistant to corrosion. It is however rapidly attacked by hydrofluoric acid, even at low concentrations. Powdered zirconium can spontaneously ignite in air. Exposed surfaces form a protective oxide layer.

Uses of Zirconium
Zirconium is very poor at absorbing neutrons. It is therefore useful in nuclear energy applications such as in the cladding (outer layer) of fuel rods through which it is important that neutrons can travel easily. Zirconium is used as to make surgical instruments and is used in steel alloys as a hardening agent. As a result of its exceptional corrosion resistance, zirconium is used extensively in the chemical industry in corrosive environments where zirconium its alloys can be found in pipes, fittings and heat exchangers. Zirconium is also used to make superconductive magnets. Zircon (zirconium silicate, ZrSiO4) is a natural gemstone and synthetic cubic zirconia (zirconium dioxide, ZrO2) is produced as a low-cost substitute for diamond. Zirconium based catalysts are used in amination, hydrogenation, isomerization and oxidation reactions. Lithium zirconate can be used to absorb carbon dioxide. The reaction is reversible so the carbon dioxide can be released in a location of choice and the lithium zirconate used again. This application may be useful in addressing environmental concerns about the release of carbon dioxide into the atmosphere.


 * Symbol:** Zr **Atomic Number:** 40 **Atomic Mass:** 91.224 amu **Melting Point:** 1852.0 °C (2125.15 K, 3365.6 °F) **Boiling Point:** 4377.0 °C (4650.15 K, 7910.6 °F) **Number of Protons/Electrons:** 40 **Number of Neutrons:** 51 **Classification:** Transition Metal **Crystal Structure:** Hexagonal **Density @ 293 K:** 6.49 g/cm3 **Color:** Grayish

Atomic Structure

 * [[image:http://www.chemicalelements.com/bohr/b0040.gif width="309" height="307"]] ||  || **Number of Energy Levels:** 5
 * First Energy Level:** **Second Energy Level:** **Third Energy Level:** **Fourth Energy Level:** **Fifth Energy Level:** ||

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Zr-86 || 16.5 hours ||
 * Zr-88 || 83.4 days ||
 * Zr-89 || 3.27 days ||
 * Zr-90 || Stable ||
 * Zr-91 || Stable ||
 * Zr-92 || Stable ||
 * Zr-93 || 1530000.0 years ||
 * Zr-94 || Stable ||
 * Zr-95 || 64.02 days ||
 * Zr-96 || Stable ||
 * Zr-97 || 16.9 hours ||

Naturally occurring zirconium contains five isotopes. Fifteen other isotopes are known to exist. Zircon, ZrSiO 4, the principal ore, is pure ZrO 2 in crystalline form having a hafnium content of about 1%. Zirconium also occurs in some 30 other recognized mineral species. Zirconium is produced commercially by reduction of chloride with magnesium (the Kroll Process), and by other methods. It is a grayish-white lustrous metal. When finely divided, the metal may ignite spontaneously in air, especially at elevated temperatures. The solid metal is much more difficult to ignite. The inherent toxicity of zirconium compounds is low. Hafnium is invariably found in zirconium ores, and the separation is difficult. Commercial-grade zirconium contains from 1 to 3% hafnium. Zirconium has a low absorption cross section for neutrons, and is therefore used for nuclear energy applications, such as for cladding fuel elements. Commercial nuclear power generation now takes more than 90% of zirconium metal production. Reactors of the commercial size, now being made, may use as much as a half-million linear feet of zirconium alloy tubing.
 * Common Isotopes:**

Zirconium has no known biological role, and zirconium compounds are of low toxicity. The human body contains, on average, only 1 milligram of zirconium, and daily intake is approximately 50 μg per day. Zirconium content in human blood is as low as 10 parts per billion. Aquatic plants readily take up soluble zirconium, but it is rare in land plants. 70% of plants have no detectable zirconium content, and those that do have as little as 5 parts per billion. Short-term exposure to zirconium powder can cause irritation, but only contact with the eyes requires medical attention. Inhalation of zirconium compounds can cause skin and lung granulomas. Zirconium aerosols can cause pulmonary granulomas. Persistent exposure to zirconium tetrachloride resulted in increased mortality in rats and guinea pigs and a decrease of blood hemoglobin and red blood cell in dogs. The U.S. Occupational Safety and Health Administration recommends a 5 mg/m3 time weighted average limit and a 10 mg/m3 short-term exposure limit for air dust.
 * Safety Dealing With Zirconium:**


 * Date of Discovery: ** 1789
 * Discoverer: ** Martin Klaproth
 * Name Origin: ** zircon (mineral)
 * Uses: ** nuclear applications
 * Obtained From: ** zircon, baddeleyite