Titanium

iso	NA	half-life	DM	DE M eV	DP
⁴⁴Ti	{syn.}	63 y	ε	0.268	⁴⁴Sc
⁴⁶Ti	8.0%	Ti is stable with 24 neutrons
⁴⁷Ti	7.3%	Ti is stable with 25 neutrons
⁴⁸Ti	73.8%	Ti is stable with 26 neutrons
⁴⁹Ti	5.5%	Ti is stable with 27 neutrons
⁵⁰Ti	5.4%	Ti is stable with 28 neutrons

SI units & STP are used except where noted.

Titanium is a chemical element in the periodic table that has the symbol Ti and atomic number 22. A light, strong, white-metallic, lustrous, corrosion-resistant transition metal, titanium is used in strong light-weight alloys and in white pigments. This element occurs in numerous minerals with the main sources being rutile and ilmenite.

Notable characteristics

Titanium is a metallic element which is well known for its excellent corrosion resistance (almost as resistant as platinum) and for its high strength-to-weight ratio. It is a light, strong, easily fabricated metal with low density (40% as dense as steel) that, when pure, is quite ductile, easy to work, lustrous, and metallic-white in color. The relatively high melting point of this element makes it useful as a refractory metal. Titanium is as strong as steel, but 45% lighter; it is 60% heavier than aluminium, but twice as strong. These properties make titanium very resistant to the usual kinds of metal fatigue.

This metal forms a passive oxide coating when exposed to air but when it is in an oxygen-free environment it is ductile. The metal, which burns when heated in air, is also the only element that can burn in pure nitrogen gas. Titanium is resistant to dilute sulfuric and hydrochloric acid, along with chlorine gas, chloride solutions, and most organic acids.

Experiments have shown that natural titanium becomes very radioactive after it is bombarded with deuterons, emitting mainly positrons and hard gamma rays. The metal is dimorphic with the hexagonal alpha form changing into the cubic beta form very slowly at around 880°C. When it is red hot the metal combines with oxygen, and when it reaches 550°C it combines with chlorine.

Applications

Approximately 95% of titanium is consumed in the form of titanium dioxide (TiO₂), an intensely white permanent pigment with good covering power in paints, paper, and plastics. Paints made with titanium dioxide are excellent reflectors of infrared radiation and are therefore used extensively by astronomers.

Because of its strength, light weight, extraordinary corrosion resistance, and ability to withstand extreme temperatures, titanium alloys are principally used in aircraft and missiles, although applications in consumer products such as golf clubs, bicycles, wedding bands, and laptop computers are becoming more common. Titanium is often alloyed with aluminium, vanadium, iron, manganese, molybdenum and with other metals. Other uses;

Due to excellent resistance to sea water, it is used to make propeller shafts and rigging.
It is used to produce relatively soft artificial gemstones.
Titanium tetrachloride (TiCl₄), a colorless liquid, is used to iridize glass and because it fumes strongly in moist air it is also used to make smoke screens.
In addition to being a very important pigment, titanium dioxide is also used in sunscreens due to its ability to protect skin by itself.
Because it is considered to be physiologically inert, the metal is used in joint replacement implants such as hip ball and sockets.
Its inertness and ability to be attractively colored makes it a popular metal for use in body piercing.
Titanium has the unusual ability to osseointegrate, enabling use in dental implants.

A potential use of titanium is in desalination plants. Titanium has occasionally been used in construction: the 150-foot memorial to Yuri Gagarin, the first man to travel in space, in Moscow, is made of titanium for the metal's attractive color and association with rocketry. The Guggenheim Museum Bilbao and the Cerritos Library were the first buildings, respectively, in Europe and North America to be sheathed in titanium panels.

History

Titanium (Latin Titans, the first sons of Gaia) was discovered in England by Reverend William Gregor in 1791 who recognized the presence of a new element in ilmenite. The element was rediscovered several years later by German chemist Martin Heinrich Klaproth in rutile ore. In 1795 Klaproth named the new element after the Titans of Greek mythology.

Pure metallic titanium (99.9%) was first prepared in 1910 by Matthew A. Hunter by heating TiCl₄ with sodium in a steel bomb at 700-800°C.

Titanium metal was not used outside the laboratory until 1946 when William Justin Kroll proved that titanium could be commercially produced by reducing titanium tetrachloride with magnesium (which is the method still used today).

Occurrence

Titanium metal is not found unbound to other elements in nature but the element is the ninth most abundant element in the Earth's crust (0.6% by mass) and is present in most igneous rocks and in sediments derived from them. It occurs primarily in the minerals anatase, brookite, ilmenite, perovskite, rutile, titanite (sphene), and in many iron ores. Of these minerals, only ilmenite and rutile have significant economic importance. Because it reacts easily with oxygen and carbon at high temperatures it is difficult to prepare pure titanium metal. Significant titanium ore deposits are in Australia, Scandinavia, North America and Malaysia.

This metal is found in meteorites and has been detected in the sun and in M-type stars. Rocks brought back from the moon during the Apollo 17 mission are composed of 12.1% TiO₂. Titanium is also found in coal ash, plants, and even the human body.

Production

Titanium (Mineral Concentrate)

Titanium metal is produced commercially by reducing TiCl₄ with magnesium, a process developed in 1946 by William Justin Kroll. This is a complex, and expensive batch process, but a newer process called the "FFC-Cambridge" method may displace this older process. This method uses the feedstock titanium dioxide powder (which is a refined form of rutile) to make the end product which is a continuous stream of molten titanium suitable for immediate use in the manufacture of commercial alloys.

It is hoped that the FFC-Cambridge method will render titanium a less rare and expensive material for the aerospace industry and the luxury goods market, and will be seen in many products currently manufactured using aluminium and specialist grades of steel.

Compounds

Although titanium metal is relatively uncommon, due to the cost of extraction, titanium dioxide is cheap, readily available in bulk, and very widely used as a white pigment in paint, plastic and construction cement. TiO₂ powder is chemically inert, resists fading in sunlight, and is very opaque: this allows it to impart a pure and brilliant white color to the brown or gray chemicals that form the majority of household plastics. Pure titanium dioxide has a very high index of refraction and an optical dispersion higher than diamond. Star sapphires and rubies get their asterism from the titanium dioxide present in them.

Isotopes

Naturally occurring titanium is composed of 5 stable isotopes; Ti-46, Ti-47, Ti-48, Ti-49 and Ti-50 with Ti-48 being the most abundant (73.8% natural abundance). Eleven radioisotopes have been characterized with the most stable being Ti-44 with a half-life of 63 years, Ti-45 with a half-life of 184.8 minutes, Ti-51 with a half-life of 5.76 minutes, and Ti-52 with a half-life of 1.7 minutes. All of the remaining radioactive isotopes have half-lifes that are less than 33 seconds and the majority of these have half lifes that are less than half a second.

The isotopes of titanium range in atomic weight from 39.99 amu (Ti-40) to 57.966 amu (Ti-58). The primary decay mode before the most abundant stable isotope, Ti-48, is electron capture and the primary mode after is beta emission. The primary decay products before Ti-48 are element 21 (scandium) isotopes and the primary products after are element 23 (vanadium) isotopes.

Precautions

When in a powdered form, titanium metal poses a significant fire hazard but salts of titanium are often considered to be relatively harmless. Chlorine compounds such as TiCl₃ and TiCl₄ should be considered to be corrosive, however. Titanium also has a tendency to bio-accumulate in tissues that contain silica but it does not play any known biological role in humans.

References

Los Alamos National Laboratory – Titanium (http://periodic.lanl.gov/elements/22.html)
Guide to the Elements – Revised Edition, Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1
USGS Titanium Statistics and Information (http://minerals.usgs.gov/minerals/pubs/commodity/titanium/)

External links

WebElements.com – Titanium (http://www.webelements.com/webelements/elements/text/Ti/index.html) (also used as a reference)
EnvironmentalChemistry.com – Titanium (http://environmentalchemistry.com/yogi/periodic/Ti.html) (also used as a reference)
High purity Titanium crystal bars - smart-elements.com (http://www.smart-elements.com/?arg=zoom&element=Ti&art=386&seite=0&total=4&linkid=ewiki-Ti#magnify)

ca:Titani da:Titanium de:Titan (Element) et:Titaan es:Titanio eo:Titanio fr:Titane it:Titanio nl:Titanium ja:チタン pl:Tytan (pierwiastek) pt:Tit�nio ru:Титан (элемент) sl:Titan fi:Titaani sv:Titan

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