Titanium

Titanium,  22Ti
Titan-crystal bar.JPG
General properties
Pronunciation-/[1] (TAY-nee-əm, ty-)
Appearancesilvery grey-white metallic
Standard atomic weight (Ar, standard)47.867(1)[2]
Titanium in the periodic table
HydrogenHelium
LithiumBerylliumBoronCarbonNitrogenOxygenFluorineNeon
SodiumMagnesiumAluminiumSiliconPhosphorusSulfurChlorineArgon
PotassiumCalciumScandiumTitaniumVanadiumChromiumManganeseIronCobaltNickelCopperZincGalliumGermaniumArsenicSeleniumBromineKrypton
RubidiumStrontiumYttriumZirconiumNiobiumMolybdenumTechnetiumRutheniumRhodiumPalladiumSilverCadmiumIndiumTinAntimonyTelluriumIodineXenon
CaesiumBariumLanthanumCeriumPraseodymiumNeodymiumPromethiumSamariumEuropiumGadoliniumTerbiumDysprosiumHolmiumErbiumThuliumYtterbiumLutetiumHafniumTantalumTungstenRheniumOsmiumIridiumPlatinumGoldMercury (element)ThalliumLeadBismuthPoloniumAstatineRadon
FranciumRadiumActiniumThoriumProtactiniumUraniumNeptuniumPlutoniumAmericiumCuriumBerkeliumCaliforniumEinsteiniumFermiumMendeleviumNobeliumLawrenciumRutherfordiumDubniumSeaborgiumBohriumHassiumMeitneriumDarmstadtiumRoentgeniumCoperniciumNihoniumFleroviumMoscoviumLivermoriumTennessineOganesson


Ti

Zr
scandiumtitaniumvanadium
Atomic number (Z)22
Groupgroup 4
Periodperiod 4
Element category  transition metal
Blockd-block
Electron configuration[Ar] 3d2 4s2
Electrons per shell
2, 8, 10, 2
Physical properties
Phase at STPsolid
Melting point1941 K ​(1668 °C, ​3034 °F)
Boiling point3560 K ​(3287 °C, ​5949 °F)
Density (near r.t.)4.506 g/cm3
when liquid (at m.p.)4.11 g/cm3
Heat of fusion14.15 kJ/mol
Heat of vaporization425 kJ/mol
Molar heat capacity25.060 J/(mol·K)
Vapor pressure
P (Pa)1101001 k10 k100 k
at T (K)19822171(2403)269230643558
Atomic properties
Oxidation states4, 3, 2, 1, −1, −2[3] ​(an amphoteric oxide)
ElectronegativityPauling scale: 1.54
Ionization energies
  • 1st: 658.8 kJ/mol
  • 2nd: 1309.8 kJ/mol
  • 3rd: 2652.5 kJ/mol
  • (more)
Atomic radiusempirical: 147 pm
Covalent radius160±8 pm
Color lines in a spectral range
Miscellanea
Crystal structurehexagonal close-packed (hcp)
Hexagonal close packed crystal structure for titanium
Speed of sound thin rod5090 m/s (at r.t.)
Thermal expansion8.6 µm/(m·K) (at 25 °C)
Thermal conductivity21.9 W/(m·K)
Electrical resistivity420 nΩ·m (at 20 °C)
Magnetic orderingparamagnetic
Magnetic susceptibility+153.0·10−6 cm3/mol (293 K)[4]
Young's modulus116 GPa
Shear modulus44 GPa
Bulk modulus110 GPa
Poisson ratio0.32
Mohs hardness6.0
Vickers hardness830–3420 MPa
Brinell hardness716–2770 MPa
CAS Number7440-32-6
History
DiscoveryWilliam Gregor (1791)
First isolationJöns Jakob Berzelius (1825)
Named byMartin Heinrich Klaproth (1795)
Main isotopes of titanium
Iso­topeAbun­danceHalf-life (t1/2)Decay modePro­duct
44Tisyn63 yε44Sc
γ
46Ti8.25%stable
47Ti7.44%stable
48Ti73.72%stable
49Ti5.41%stable
50Ti5.18%stable
| references | in Wikidata

Titanium is a chemical element with symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine.

Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791, and was named by Martin Heinrich Klaproth after the Titans of Greek mythology. The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere, and it is found in almost all living things, water bodies, rocks, and soils.[5] The metal is extracted from its principal mineral ores by the Kroll[6] and Hunter processes. The most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments.[7] Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and catalysts; and titanium trichloride (TiCl3), which is used as a catalyst in the production of polypropylene.[5]

Titanium can be alloyed with iron, aluminium, vanadium, and molybdenum, among other elements, to produce strong, lightweight alloys for aerospace (jet engines, missiles, and spacecraft), military, industrial processes (chemicals and petrochemicals, desalination plants, pulp, and paper), automotive, agri-food, medical prostheses, orthopedic implants, dental and endodontic instruments and files, dental implants, sporting goods, jewelry, mobile phones, and other applications.[5]

The two most useful properties of the metal are corrosion resistance and strength-to-density ratio, the highest of any metallic element.[8] In its unalloyed condition, titanium is as strong as some steels, but less dense.[9] There are two allotropic forms[10] and five naturally occurring isotopes of this element, 46Ti through 50Ti, with 48Ti being the most abundant (73.8%).[11] Although they have the same number of valence electrons and are in the same group in the periodic table, titanium and zirconium differ in many chemical and physical properties.

Characteristics

Physical properties

As a metal, titanium is recognized for its high strength-to-weight ratio.[10] It is a strong metal with low density that is quite ductile (especially in an oxygen-free environment),[5] lustrous, and metallic-white in color.[12] The relatively high melting point (more than 1,650 °C or 3,000 °F) makes it useful as a refractory metal. It is paramagnetic and has fairly low electrical and thermal conductivity.[5]

Commercially pure (99.2% pure) grades of titanium have ultimate tensile strength of about 434 MPa (63,000 psi), equal to that of common, low-grade steel alloys, but are less dense. Titanium is 60% denser than aluminium, but more than twice as strong[9] as the most commonly used 6061-T6 aluminium alloy. Certain titanium alloys (e.g., Beta C) achieve tensile strengths of over 1,400 MPa (200,000 psi).[13] However, titanium loses strength when heated above 430 °C (806 °F).[14]

Titanium is not as hard as some grades of heat-treated steel; it is non-magnetic and a poor conductor of heat and electricity. Machining requires precautions, because the material can gall unless sharp tools and proper cooling methods are used. Like steel structures, those made from titanium have a fatigue limit that guarantees longevity in some applications.[12]

The metal is a dimorphic allotrope of an hexagonal α form that changes into a body-centered cubic (lattice) β form at 882 °C (1,620 °F).[14] The specific heat of the α form increases dramatically as it is heated to this transition temperature but then falls and remains fairly constant for the β form regardless of temperature.[14]

Chemical properties

The Pourbaix diagram for titanium in pure water, perchloric acid, or sodium hydroxide[15]

Like aluminium and magnesium, titanium metal and its alloys oxidize immediately upon exposure to air. Titanium readily reacts with oxygen at 1,200 °C (2,190 °F) in air, and at 610 °C (1,130 °F) in pure oxygen, forming titanium dioxide.[10] It is, however, slow to react with water and air at ambient temperatures because it forms a passive oxide coating that protects the bulk metal from further oxidation.[5] When it first forms, this protective layer is only 1–2 nm thick but continues to grow slowly; reaching a thickness of 25 nm in four years.[16]

Atmospheric passivation gives titanium excellent resistance to corrosion, almost equivalent to platinum. Titanium is capable of withstanding attack by dilute sulfuric and hydrochloric acids, chloride solutions, and most organic acids.[6] However, titanium is corroded by concentrated acids.[17] As indicated by its negative redox potential, titanium is thermodynamically a very reactive metal that burns in normal atmosphere at lower temperatures than the melting point. Melting is possible only in an inert atmosphere or in a vacuum. At 550 °C (1,022 °F), it combines with chlorine.[6] It also reacts with the other halogens and absorbs hydrogen.[7]

Titanium is one of the few elements that burns in pure nitrogen gas, reacting at 800 °C (1,470 °F) to form titanium nitride, which causes embrittlement.[18] Because of its high reactivity with oxygen, nitrogen, and some other gases, titanium filaments are applied in titanium sublimation pumps as scavengers for these gases. Such pumps inexpensively and reliably produce extremely low pressures in ultra-high vacuum systems.

Occurrence

2011 production of rutile and ilmenite[19]
Country thousand
tonnes
% of total
Australia 1,300 19.4
South Africa 1,160 17.3
Canada 700 10.4
India 574 8.6
Mozambique 516 7.7
China 500 7.5
Vietnam 490 7.3
Ukraine 357 5.3
World 6,700 100

Titanium is the ninth-most abundant element in Earth's crust (0.63% by mass)[20] and the seventh-most abundant metal. It is present as oxides in most igneous rocks, in sediments derived from them, in living things, and natural bodies of water.[5][6] Of the 801 types of igneous rocks analyzed by the United States Geological Survey, 784 contained titanium. Its proportion in soils is approximately 0.5 to 1.5%.[20]

Common titanium-containing minerals are anatase, brookite, ilmenite, perovskite, rutile, and titanite (sphene).[16] Akaogiite is an extremely rare mineral consisting of titanium dioxide. Of these minerals, only rutile and ilmenite have economic importance, yet even they are difficult to find in high concentrations. About 6.0 and 0.7 million tonnes of those minerals were mined in 2011, respectively.[19] Significant titanium-bearing ilmenite deposits exist in western Australia, Canada, China, India, Mozambique, New Zealand, Norway, Sierra Leone, South Africa, and Ukraine.[16] About 186,000 tonnes of titanium metal sponge were produced in 2011, mostly in China (60,000 t), Japan (56,000 t), Russia (40,000 t), United States (32,000 t) and Kazakhstan (20,700 t). Total reserves of titanium are estimated to exceed 600 million tonnes.[19]

The concentration of titanium is about 4 picomolar in the ocean. At 100 °C, the concentration of titanium in water is estimated to be less than 10−7 M at pH 7. The identity of titanium species in aqueous solution remains unknown because of its low solubility and the lack of sensitive spectroscopic methods, although only the 4+ oxidation state is stable in air. No evidence exists for a biological role, although rare organisms are known to accumulate high concentrations of titanium.[21]

Titanium is contained in meteorites, and it has been detected in the Sun and in M-type stars[6] (the coolest type) with a surface temperature of 3,200 °C (5,790 °F).[22] Rocks brought back from the Moon during the Apollo 17 mission are composed of 12.1% TiO2.[6] It is also found in coal ash, plants, and even the human body. Native titanium (pure metallic) is very rare.[23]

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, the most stable being 44Ti with a half-life of 63 years; 45Ti, 184.8 minutes; 51Ti, 5.76 minutes; and 52Ti, 1.7 minutes. All the other radioactive isotopes have half-lives less than 33 seconds and the majority, less than half a second.[11]

The isotopes of titanium range in atomic weight from 39.99 u (40Ti) to 57.966 u (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.[11]

Titanium becomes radioactive upon bombardment with deuterons, emitting mainly positrons and hard gamma rays.[6]

Other Languages
Afrikaans: Titaan
አማርኛ: ቲታኒየም
العربية: تيتانيوم
aragonés: Titanio
armãneashti: Titaniu
asturianu: Titaniu
azərbaycanca: Titan
تۆرکجه: تیتانیوم
Bân-lâm-gú: Titanium
беларуская (тарашкевіца)‎: Тытан
भोजपुरी: टाइटैनियम
български: Титан (елемент)
བོད་ཡིག: ཊའི་ཊི་ནིམ།
bosanski: Titanij
brezhoneg: Titaniom
català: Titani
Cebuano: Titanyo
čeština: Titan (prvek)
corsu: Titaniu
Cymraeg: Titaniwm
eesti: Titaan
Ελληνικά: Τιτάνιο
español: Titanio
euskara: Titanio
فارسی: تیتانیم
Fiji Hindi: Titanium
français: Titane
furlan: Titani
Gaeilge: Tíotáiniam
Gàidhlig: Titanium
galego: Titanio
贛語:
Gĩkũyũ: Titanium
ગુજરાતી: ટાઇટેનિયમ
客家語/Hak-kâ-ngî: Titanium
хальмг: Титан
한국어: 타이타늄
Hawaiʻi: Titanium
Հայերեն: Տիտան
हिन्दी: टाइटेनियम
hrvatski: Titanij
Ido: Titanio
Bahasa Indonesia: Titanium
interlingua: Titanium
íslenska: Títan
italiano: Titanio
עברית: טיטניום
Basa Jawa: Titanium
ქართული: ტიტანი
қазақша: Титан
Kiswahili: Titani
Kreyòl ayisyen: Titàn
kurdî: Tîtan
Кыргызча: Титан
кырык мары: Титан (элемент)
Latina: Titanium
latviešu: Titāns
Lëtzebuergesch: Titan (Element)
lietuvių: Titanas
Ligure: Titanio
Limburgs: Titanium
Livvinkarjala: Titanium
la .lojban.: jinmrtitani
lumbaart: Titanio
македонски: Титан
മലയാളം: ടൈറ്റാനിയം
Bahasa Melayu: Titanium
Mìng-dĕ̤ng-ngṳ̄: Titanium
монгол: Титан
မြန်မာဘာသာ: တိုင်‌တေနီယမ်
Nederlands: Titanium
नेपाली: टाइटानियम
नेपाल भाषा: टाइटानियम
日本語: チタン
Nordfriisk: Titan
norsk nynorsk: Grunnstoffet titan
occitan: Titani
ଓଡ଼ିଆ: ଟିଟାନିଅମ
oʻzbekcha/ўзбекча: Titan (unsur)
ਪੰਜਾਬੀ: ਟਾਈਟੇਨੀਅਮ
پنجابی: ٹائٹینیم
Piemontèis: Titani
Plattdüütsch: Titan (Element)
português: Titânio
română: Titan
Runa Simi: Titanyu
संस्कृतम्: टाइटेनियम्
Scots: Titanium
Seeltersk: Titan (Element)
shqip: Titani
sicilianu: Titaniu
Simple English: Titanium
slovenčina: Titán (prvok)
slovenščina: Titan (element)
Soomaaliga: Titaaniyaam
کوردی: تیتانیۆم
српски / srpski: Титанијум
srpskohrvatski / српскохрватски: Titanij
Basa Sunda: Titanium
suomi: Titaani
svenska: Titan
Tagalog: Titanyo
татарча/tatarça: Титан
తెలుగు: టైటానియం
Türkçe: Titanyum
ئۇيغۇرچە / Uyghurche: تىتان
vepsän kel’: Titan (himine element)
Tiếng Việt: Titan
文言:
Winaray: Titanyo
吴语:
ייִדיש: טיטאניום
Yorùbá: Titaniomu
粵語:
中文:
Kabɩyɛ: Tɩtanɩyɔm