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Titanium

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                22             scandium ← titanium → vanadium
                 -
                ↑
                Ti
                ↓
                Zr

                                  Periodic Table - Extended Periodic Table

                                                                   General
                                     Name, Symbol, Number titanium, Ti, 22
                                         Chemical series transition metals
                                              Group, Period, Block 4, 4, d
                                               Appearance silvery metallic
                                              Atomic mass 47.867 (1) g/mol
                                     Electron configuration [Ar] 3d^2 4s^2
                                           Electrons per shell 2, 8, 10, 2
                                                       Physical properties
                                                               Phase solid
                                      Density (near r.t.) 4.506 g·cm^−3
                                    Liquid density at m.p. 4.11 g·cm^−3
                                                     Melting point 1941  K
                                                    (1668 ° C, 3034 ° F)
                                                      Boiling point 3560 K
                                                    (3287 ° C, 5949 ° F)
                                         Heat of fusion 14.15 kJ·mol^−1
                                     Heat of vaporization 425 kJ·mol^−1
                         Heat capacity (25 °C) 25.060 J·mol^−1·K^−1

   CAPTION: Vapor pressure

                                    P/Pa   1    10   100   1 k  10 k 100 k
                                   at T/K 1982 2171 (2403) 2692 3064 3558

                                                         Atomic properties
                                               Crystal structure hexagonal
                                                  Oxidation states 2, 3, 4
                                                       ( amphoteric oxide)
                                    Electronegativity 1.54 (Pauling scale)
                                                       Ionization energies
                                           ( more) 1st: 658.8 kJ·mol^−1
                                                  2nd: 1309.8 kJ·mol^−1
                                                  3rd: 2652.5 kJ·mol^−1
                                                      Atomic radius 140 pm
                                              Atomic radius (calc.) 176 pm
                                                    Covalent radius 136 pm
                                                             Miscellaneous
                                            Magnetic ordering paramagnetic
                             Electrical resistivity (20 °C) 0.420 µΩ·m
                       Thermal conductivity (300 K) 21.9 W·m^−1·K^−1
                        Thermal expansion (25 °C) 8.6 µm·m^−1·K^−1
                        Speed of sound (thin rod) ( r.t.) 5090   m·s^−1
                                                   Young's modulus 116 GPa
                                                      Shear modulus 44 GPa
                                                      Bulk modulus 110 GPa
                                                        Poisson ratio 0.32
                                                         Mohs hardness 6.0
                                                  Vickers hardness 970 MPa
                                                  Brinell hardness 716 MPa
                                             CAS registry number 7440-32-6
                                                         Selected isotopes

                 CAPTION: Main article: Isotopes of titanium

                               iso   NA   half-life DM   DE ( MeV)    DP
                              ^44Ti syn   63 y      ε  -             ^44Sc
                                                    γ  0.07 D, 0.08D -
                              ^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

                                                                References

   Titanium ( IPA: /tʌɪˈteɪniəm/) is a chemical element in the periodic
   table that has the symbol Ti and atomic number 22. It is a light,
   strong, lustrous, corrosion-resistant (including resistance to sea
   water and chlorine) transition metal with a white-silvery-metallic
   colour. Titanium is used in strong lightweight alloys (most notably
   with iron and aluminium), and in powdered form to other materials, such
   as graphite composites. Its most common compound, titanium dioxide, is
   used in white pigments.

   The element occurs in numerous minerals with the main sources being
   rutile and ilmenite, which are widely distributed over the Earth. There
   are two allotropic forms and five naturally occurring isotopes of this
   element; ^46Ti through ^50Ti with ^48Ti being the most abundant
   (73.8%). One of titanium's most notable characteristics is that it is
   as strong as steel but is only 60% its density. Titanium's properties
   are chemically and physically similar to zirconium.

History

   Titanium was discovered at Creed, Cornwall, in England by amateur
   geologist Reverend William Gregor in 1791. He recognized the presence
   of a new element in ilmenite, and named it menachite (alternately
   spelled manaccanite), after the nearby parish of Manaccan . Around the
   same time, Franz Joseph Muller also produced a similar substance, but
   could not identify it. The element was independently rediscovered
   several years later by German chemist Martin Heinrich Klaproth in
   rutile ore. Klaproth confirmed it as a new element and in 1795 he named
   it for the Titans of Greek mythology.

   The metal has always been difficult to extract from its various ores.
   Pure metallic titanium (99.9%) was first prepared in 1910 by Matthew A.
   Hunter by heating TiCl[4] with sodium in a steel bomb at 700–800 °C in
   the Hunter process. 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
   in the Kroll process which is the method still used today.

   In 1950– 1960s the Soviet Union attempted to corner the world titanium
   market as a tactic in the Cold War to prevent the American military
   from utilizing it. In spite of these efforts, the U.S. obtained large
   quantities of titanium when a European company set up a front for the
   U.S. foreign intelligence agencies to purchase it. Indeed, titanium for
   the highly successful U.S. SR-71 reconnaissance aircraft was acquired
   from the Soviet Union at the height of the Cold War.

Chemistry

   Titanium is well known for its excellent resistance to corrosion; it is
   almost as resistant as platinum, being able to withstand attack by
   acids, moist chlorine gas, and by common salt solutions. Pure titanium
   is not soluble in water but is soluble in concentrated acids. A
   metallic element, it is also well-known for its high strength-to-weight
   ratio. It is a light, strong metal with low density that, when pure, is
   quite ductile (especially in an oxygen-free environment), lustrous, and
   metallic-white in colour. The relatively high melting point of this
   element makes it useful as a refractory metal. Commercially pure grades
   of titanium have an ultimate tensile strength equal to that of high
   strength low alloy steels, but are 43% lighter. Titanium is 60% heavier
   than aluminium, but more than twice as strong as 6061-T6 aluminium
   alloy; these numbers can vary quite substantially due to different
   alloy compositions and processing variables. It is fairly hard
   (although by no means as hard as some grades of heat-treated steel) and
   has a tendency to blunt cutting tools. Like those made from steel,
   titanium structures have a fatigue limit which guarantees longevity in
   some applications.

   This metal forms a passive and protective oxide coating (leading to
   corrosion-resistance) when exposed to elevated temperatures in air, but
   at room temperatures it resists tarnishing. The metal, which burns when
   heated in air 610 °C or higher (forming titanium dioxide) is also one
   of the few elements that burns in pure nitrogen gas (it burns at 800 °C
   and forms titanium nitride). Titanium is resistant to dilute sulfuric
   and hydrochloric acid, along with chlorine gas, chloride solutions, and
   most organic acids. It is paramagnetic (weakly attracted to magnets)
   and has fairly low electrical conductivity and thermal conductivity.

   Experiments have shown that natural titanium becomes radioactive after
   it is bombarded with deuterons, emitting mainly positrons and hard
   gamma rays. The metal is a dimorphic allotrope 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. It also reacts with the other
   halogens and absorbs hydrogen.

Isotopes

   Naturally occurring titanium is composed of 5 stable isotopes; ^46Ti,
   ^47Ti, ^48Ti, ^49Ti and ^50Ti with ^48Ti being the most abundant (73.8%
   natural abundance). Eleven radioisotopes have been characterized, with
   the most stable being ^44Ti with a half-life of 63 years, ^45Ti with a
   half-life of 184.8 minutes, ^51Ti with a half-life of 5.76 minutes, and
   ^52Ti 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 (^40Ti)
   to 57.966 amu (^58Ti). The primary decay mode before the most abundant
   stable isotope, ^48Ti, is electron capture and the primary mode after
   is beta emission. The primary decay products before ^48Ti are element
   21 (scandium) isotopes and the primary products after are element 23
   (vanadium) isotopes.

Occurrence

   Titanium metal is always bonded to other elements in nature. It is the
   ninth-most abundant element in the Earth's crust (0.63% by mass) and is
   present in most igneous rocks and in sediments derived from them (as
   well as in living things and natural bodies of water). It is widely
   distributed and occurs primarily in the minerals anatase, brookite,
   ilmenite, perovskite, rutile, titanite (sphene), as well in many iron
   ores. Of these minerals, only ilmenite and rutile have significant
   economic importance, yet even they are difficult to find in high
   concentrations. Significant titanium ore deposits exist in Australia,
   New Zealand, Scandinavia, North America, and Malaysia. Large quantities
   have also been detected in the Kwale region in Kenya, deposits to which
   a Canadian firm, Tiomin, has mining rights.
     Producer   Thousands of tons % of total
    Australia        1291.0          30.6
   South Africa       850.0          20.1
      Canada          767.0          18.2
      Norway          382.9          9.1
     Ukraine          357.0          8.5
   Total: top 5      3647.9          86.5
   Total world       4221.0         100.0

   Chiffres de 2003, en milliers de tonnes de dioxide de titane

   Source ; L'état du monde 2005, annuaire économique géopolique mondial

   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% TiO[2]. Titanium is also found in coal
   ash, plants, and even the human body (while harmless, it is not
   believed to be an essential element).
   Titanium (Mineral Concentrate)
   Enlarge
   Titanium (Mineral Concentrate)

   By 1956 U.S. production of titanium mill products was more than 6
   million kg/yr.

Production by isolation

   Because the metal reacts with air at high temperatures it cannot be
   produced by reduction of its dioxide. Titanium metal is therefore
   produced commercially by the Kroll process, a complex and expensive
   batch process developed in 1946 by William Justin Kroll. In the Kroll
   process, the oxide is first converted to chloride through
   carbochlorination, whereby chlorine gas is passed over red-hot rutile
   or ilmenite in the presence of carbon to make TiCl[4]. This is
   condensed and purified by fractional distillation and then reduced with
   800 °C molten magnesium in an argon atmosphere.

   A newer process, the FFC Cambridge Process, may replace the older Kroll
   process. This method uses the feedstock titanium dioxide powder (which
   is a refined form of rutile) to make the end product which is either a
   powder or sponge. If mixed oxide powders are used, the product is an
   alloy at a much lower cost than the conventional multi-step melting
   process. It is hoped that the FFC Cambridge Process 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.

   Titanium was purified to ultra high purity in small quantities when
   Anton Eduard van Arkel and Jan Hendrik de Boer discovered the iodide,
   or crystal bar, process in 1925, by reacting with iodine and
   decomposing the formed vapors over a hot filament to pure metal.

   Titanium oxide is produced commercially by grinding its mineral ore and
   mixing it with potassium carbonate and aqueous hydrofluoric acid. This
   yields potassium fluorotitanate (K[2]TiF[6]) which is extracted with
   hot water and decomposed with ammonia, producing an ammoniacal hydrated
   oxide. This in turn is ignited in a platinum vessel, which creates pure
   titanium dioxide.

   Common titanium alloys are made by reduction. For example;
   cuprotitanium (rutile with copper added is reduced), ferrocarbon
   titanium (ilmenite reduced with coke in an electric furnace), and
   manganotitanium (rutile with manganese or manganese oxides) are
   reduced.

Applications

   watch with titanium cover
   Enlarge
   watch with titanium cover

   About 95% of titanium production is consumed in the form of titanium
   dioxide (TiO[2]), an intensely white permanent pigment with good
   covering power in paints, paper, toothpaste, and plastics. Paints made
   with titanium dioxide are excellent reflectors of infrared radiation
   and are therefore used extensively by astronomers and in exterior
   paints. It is also used in cement, in gemstones, as an optical
   opacifier in paper (Smook 2002), and a strengthening agent in graphite
   composite fishing rods and golf clubs. Recently, it has been put to use
   in air purifiers (as a filter coating), or in film used to coat windows
   on buildings which when exposed to UV light (either solar or man-made)
   and moisture in the air produces reactive redox species like hydroxyl
   radicals that can purify the air or keep window surfaces clean.

   Because of its high tensile strength (even at high temperatures), light
   weight, extraordinary corrosion resistance, and ability to withstand
   extreme temperatures, titanium alloys are used in aircraft, armour
   plating, naval ships, spacecraft, and missiles. It is used in steel
   alloys to reduce grain size and as a deoxidizer, and in stainless steel
   to reduce carbon content. Titanium is often alloyed with aluminium (to
   refine grain size), vanadium, copper (to harden), iron, manganese,
   molybdenum, and with other metals.

   Welded titanium pipe is used in the chemical industry for its corrosion
   resistance and is seeing growing use in petroleum drilling, especially
   offshore, for its strength, light weight, and corrosion resistance.

   Titanium alloyed with vanadium is used in the outer skin of aircraft,
   fire walls, landing gear, and hydraulic tubing. An estimated 58 tons of
   the metal is used in the Boeing 777, 43 in the 747, 18 in the 737, 24
   in the Airbus A340, 17 in the A330 and 12 in the A320, according to the
   2004 annual report of the Titanium Metals Corporation. Generally, newer
   models use more and widebodies use the most. The A380 may use 77 tons,
   including about 10 or 11 tons in the engines.

   Use of titanium in consumer products such as tennis rackets, golf
   clubs, lacrosse stick shafts, cricket helmet grills, bicycle frames,
   laboratory equipment, wristwatches, wedding bands, and laptop computers
   is becoming more common. Titanium alloys are also used in spectacle
   frames. This results in a rather expensive, but highly durable and long
   lasting frame which is light in weight and causes no skin allergies.
   Both traditional alloys and shape memory alloys find use in this
   application. Many backpackers use titanium equipment, including
   cookware, eating utensils, lanterns and tent stakes. Though slightly
   more expensive than traditional steel or aluminium alternatives, these
   titanium products can be significantly lighter without compromising
   strength. However, the thermal properties of titanium cookware can
   cause uneven heating without a well-distributed heat source, which may
   make it unsuitable for some culinary applications.

   Its inertness and ability to be attractively coloured makes it a
   popular metal for use in body piercing. Titanium may be anodised to
   produce various colours.

Construction

   Titanium has occasionally been used in construction: the 150-foot (45
   m) memorial to Yuri Gagarin, the first man to travel in space, in
   Moscow, is made of titanium for the metal's attractive colour and
   association with rocketry. The Guggenheim Museum Bilbao and the
   Cerritos Millennium Library were the first buildings in Europe and
   North America, respectively, to be sheathed in titanium panels. Other
   construction uses of titanium sheathing include the Frederic C.
   Hamilton Building in ( Denver, Colorado).

   Due to excellent resistance to sea water, it is used to make propeller
   shafts and rigging and in the heat exchangers of desalination plants
   and in heater-chillers for salt water aquariums, fishing line and
   leader, and lately diver knives as well. As there are substantial ore
   deposits in Russia, it was the principal material used in the
   construction of many advanced Russian submarines, including
   deepest-diving military submarines to date, Alfa and Mike class, as
   well as Typhoon class.

Medical applications

   A titanium hip prosthesis, with a ceramic head and polyethylene
   acetabular cup.
   Enlarge
   A titanium hip prosthesis, with a ceramic head and polyethylene
   acetabular cup.

   Because it is considered to be physiologically inert, the metal is used
   in joint replacement implants such as hip ball and sockets and to make
   medical equipment and in pipe/tank lining in food processing. Since
   titanium is non- ferromagnetic, patients with titanium implants can be
   safely examined with magnetic resonance imaging (convenient for
   long-term implants). Titanium is also used for the surgical instruments
   used in image-guided surgery.

   Titanium has the unusual ability to osseointegrate, enabling use in
   dental implants. This ability is also exploited by some orthopaedic
   implants. Orthopaedic applications also take advantage of titainium's
   lower modulus of elasticity to more closely match the modulus of the
   bone that such devices are intended to repair. As a result, skeletal
   loads are more evenly shared between bone and implant leading to a
   lower incidence of bone degredation from stress shielding and
   periprosthetic bone fractures which occur at the boundaries of
   orthopaedic implants which act as stress risers. However, titanium
   alloys' stiffness is still more than twice that of bone, eventually
   leading to joint degradation.

Compounds

   The +4 oxidation state dominates in titanium chemistry, but compounds
   in the +3 oxidation state are also common. Because of this high
   oxidation state, many titanium compounds have a high degree of covalent
   bonding.

   Although titanium metal is relatively uncommon, due to the cost of
   extraction, titanium dioxide (also called titanium(IV), titanium white,
   or even titania) is cheap, nontoxic, readily available in bulk, and
   very widely used as a white pigment in paint, enamel, lacquer, plastic
   and construction cement. TiO[2] powder is chemically inert, resists
   fading in sunlight, and is very opaque: this allows it to impart a pure
   and brilliant white colour to the brown or gray chemicals that form the
   majority of household plastics. In nature, this compound is found in
   the minerals anatase, brookite, and rutile.

   Paint made with titanium dioxide does well in severe temperatures, is
   somewhat self-cleaning, and stands up to marine environments. 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. Titanates are
   compounds made with titanium dioxide. Barium titanate has piezoelectric
   properties, thus making it possible to use it as a transducer in the
   interconversion of sound and electricity. Esters of titanium are formed
   by the reaction of alcohols and titanium tetrachloride and are used to
   waterproof fabrics.

   Titanium nitride is often used to coat cutting tools, such as drill
   bits. It also finds use as a gold-coloured decorative finish, and as a
   barrier metal in semiconductor fabrication.

   Titanium(IV) chloride (titanium tetrachloride, TiCl[4], sometimes
   called "Tickle") is a colourless, weakly acidic liquid which is used as
   an intermediate in the manufacture of titanium(IV) oxide for paint. It
   is widely used in organic chemistry as a Lewis acid, for example in the
   Mukaiyama aldol condensation. Titanium also forms a lower chloride,
   titanium(III) chloride (TiCl[3]), which is used as a reducing agent.

   Titanocene dichloride is an important catalyst for carbon-carbon bond
   formation. Titanium isopropoxide is used for Sharpless epoxidation.
   Other compounds include; Titanium bromide (used in metallurgy,
   superalloys, and high-temperature electrical wiring and coatings) and
   titanium carbide (found in high-temperature cutting tools and
   coatings).

Safety

   As a powder or in the form of metal shavings, titanium metal poses a
   significant fire hazard and, when heated in air, an explosion hazard.
   Water and carbon dioxide-based methods to extinguish fires are
   ineffective on burning titanium; Class D dry powder fire fighting
   agents must be used instead.

   Salts of titanium are often considered to be relatively harmless but
   its chlorine compounds, such as TiCl[2], TiCl[3] and TiCl[4], have
   unusual hazards. The dichloride takes the form of pyrophoric black
   crystals, and the tetrachloride is a volatile fuming liquid. All of
   titanium's chlorides are corrosive. Titanium also has a tendency to
   bio-accumulate in tissues that contain silica but it does not play any
   known biological role in humans.

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