| Discovery date | 1791 |
| Discovered by | William Gregor |
| Origin of the name | The name is derived from the Titansthe sons of the Earth goddess of Greek mythology. |
| Allotropes |
|
Ti
Titanium
22
47.867
| Group | 4 | Melting point | 1670°C3038°F1943 K |
| Period | 4 | Boiling point | 3287°C5949°F3560 K |
| Block | d | Density (g cm−3) | 4.506 |
| Atomic number | 22 | Relative atomic mass | 47.867 |
| State at 20°C | Solid | Key isotopes | 48Ti |
| Electron configuration | [Ar] 3d24s2 | CAS number | 7440-32-6 |
| ChemSpider ID | 22402 | ChemSpider is a free chemical structure database | |
Image explanation
The symbol is representative of the Titans of Greek mythologyafter which the element is named. It is based on early votive offering figurines.
Appearance
A hardshiny and strong metal.
Uses
Titanium is as strong as steel but much less dense. It is therefore important as an alloying agent with many metals including aluminiummolybdenum and iron. These alloys are mainly used in aircraftspacecraft and missiles because of their low density and ability to withstand extremes of temperature. They are also used in golf clubslaptopsbicycles and crutches.
Power plant condensers use titanium pipes because of their resistance to corrosion. Because titanium has excellent resistance to corrosion in seawaterit is used in desalination plants and to protect the hulls of shipssubmarines and other structures exposed to seawater.
Titanium metal connects well with boneso it has found surgical applications such as in joint replacements (especially hip joints) and tooth implants.
The largest use of titanium is in the form of titanium(IV) oxide. It is extensively used as a pigment in house paintartists’ paintplasticsenamels and paper. It is a bright white pigment with excellent covering power. It is also a good reflector of infrared radiation and so is used in solar observatories where heat causes poor visibility.
Titanium(IV) oxide is used in sunscreens because it prevents UV light from reaching the skin. Nanoparticles of titanium(IV) oxide appear invisible when applied to the skin.
Biological role
Titanium has no known biological role. It is non-toxic. Fine titanium dioxide dust is a suspected carcinogen.
Natural abundance
Titanium is the ninth most abundant element on Earth. It is almost always present in igneous rocks and the sediments derived from them. It occurs in the minerals ilmeniterutile and sphene and is present in titanates and many iron ores.
Titanium is produced commercially by reducing titanium(IV) chloride with magnesium. Titanium(IV) oxide is produced commercially by either the ‘sulfate process’ or the ‘chloride process’both of which use the mineral ilmenite as a starting material.
History
The first titanium minerala black sand called menachanitewas discovered in 1791 in Cornwall by the Reverend William Gregor. He analysed it and deduced it was made up of the oxides of iron and an unknown metaland reported it as such to the Royal Geological Society of Cornwall.
In 1795the German scientist Martin Heinrich Klaproth of Berlin investigated a red ore known as Schörl from Hungary. This is a form of rutile (TiO2) and Klaproth realised it was the oxide of a previously unknown element which he named titanium. When he was told of Gregor’s discovery he investigated menachanite and confirmed it too contained titanium.
It was not until 1910 that M. A. Hunterworking for General Electric in the USAmade pure titanium metal by heating titanium tetrachloride and sodium metal.
| Atomic radiusnon-bonded (Å) | 2.11 | Covalent radius (Å) | 1.48 |
| Electron affinity (kJ mol−1) | 7.622 |
Electronegativity (Pauling scale) |
1.54 |
|
Ionisation energies (kJ mol−1) |
1st
658.813
2nd
1309.837
3rd
2652.546
4th
4174.651
5th
9581
6th
11532.89
7th
13585.1
8th
16441.1
|
||
| Common oxidation states | 43 | ||||
| Isotopes | Isotope | Atomic mass | Natural abundance (%) | Half life | Mode of decay |
| 46Ti | 45.953 | 8.25 | - | - | |
| 47Ti | 46.952 | 7.44 | - | - | |
| 48Ti | 47.948 | 73.72 | - | - | |
| 49Ti | 48.948 | 5.41 | - | - | |
| 50Ti | 49.945 | 5.18 | - | - | |
|
|
|
Specific heat capacity (J kg−1 K−1) |
524 | Young's modulus (GPa) | 115.7 | |||||||||||
| Shear modulus (GPa) | 43.8 | Bulk modulus (GPa) | Unknown | |||||||||||
| Vapour pressure | ||||||||||||||
| Temperature (K) |
|
|||||||||||||
| Pressure (Pa) |
|
|||||||||||||
Podcasts
| Listen to Titanium Podcast |
|
Transcript :
Chemistry in its element: titanium(Promo) You're listening to Chemistry in its element brought to you by Chemistry Worldthe magazine of the Royal Society of Chemistry. (End promo) Meera Senthilingam This weekyou may be surprised to learn just how reliant you are on this widely used element that cleans and protects our environment. Simon Cotton Titanium. It is notoriously hard to makebut we have come to rely on it and indeed we couldn't do without this element or its compounds today. Sowhy is it so important? The most important compound is the oxide TiO2which makes up 95% of the Ti used worldwide. We actually use 4 million tons of TiO2 each yeara lot of it for paint and other applications that need something that is bright whiteinsoluble and not toxiclike medicines and toothpaste. In the food industry it is additive number E171used to whiten things like confectionarycheesesicings and toppings. It is also used in sunscreenssince it is a very opaque white and also very good at absorbing UV light. The ability to absorb UV light helps the TiO2 to act as a photocatalyst. This means that when UV light falls upon itit generates free electrons that react with molecules on the surfaceforming very reactive organic free radicals. Now you don't want these radicals on your skinso the TiO2 used in sunscreens is coated with a protective layer of silica or alumina. In other situationsthese radicals can be a good thingas they can kill bacteria. Scientists have found that if you introduce small amounts of different elements like nitrogen or silver into the TiO2UV light is not needed as visible light will do the same job. You can put very thin coatings of TiO2 onto glass (or other substances like tiles); these are being tested in hospitalsas a way of reducing infections. When water gets onto this type of glassit spreads outso that it doesn't fog up (think car wing mirrors) and also washes away dirt. This is the basis of Pilkington's ActivT self-cleaning glassa great British invention. Scientists are now investigating building TiO2 into the surfaces of buildingspavements and roadswith the aim of getting rid of chewing gum and even dog mess. They are also testing road surfaces with a layer of TiO2 in itas they think it could remove air pollutants from car exhausts. The first titanium compound was identified by a Cornish vicar named William Gregor in 1791when he extracted the impure oxide. He dissolved it in acid and got a colourless solutionbut found that it could be reduced by zinc to make a purple solution. He was a transition metal chemist ahead of his time. Lots of chemists tried - for over a hundred years - to get the pure metal. We now know that this is very difficult because even the normally unreactive gas nitrogen reacts with hot titanium metal to form the nitrideTiN. Nowadays titanium is manufactured by the Kroll process. First you heat titanium dioxide with carbon to about 1000 degrees C and pass chlorine over it. This makes TiCl4. People call that "Tickle". Then you cover the Tickle with an argon blanket and react with hot magnesium [at 850 degrees C] to get the metallic element. Titanium metal is not as cheap as iron - because it is more difficult to extract - so its applications tend to be specialist ones. Titanium metal has some very valuable properties. In practiceit is pretty unreactive becauselike aluminiumit forms a thin protective layer of the oxideso it doesn't corrode. Its density is 4.5 grams per cm3much less than ironso titanium alloys are important in the aerospace industry. It was used to make much of the SR-71 Blackbirdthe world's fastest manned aircraftas well as a major parts of the engines and airframe of the big passenger aircraft including 747s and Airbuses. This metal is resistant to seawater so it finds marine applications like propeller shaftsand the Russians are said to have used it to construct submarines. Titanium isn't toxicand it is not rejected by the body. It also connects with boneso it has found surgical applications such as in joint replacements - especially hip joints - and tooth implants. So there are lots of applications for titanium and its compounds - we just can't do without it. Meera Senthilingam Indeed we can'tseeing as it's in our foodsunscreen and windowsand soon may even be in our hospitals and on our roads. That was Simon Cotton from Uppingham School with the diverse uses and chemistry of titanium. Now next weeka sparkling element that makes otherwise plain minerals into precious stones. Christopher Blanford Of all chromium's natural occurrencesmy favourites are gemstoneswhere a trace of the element adds a blaze of colour. As corundumberyland crysoberylthese metal oxides are colourless and obscure minerals. But add a dash of chromiumand they become rubyemerald and alexandrite. In ruby - which is aluminium oxide with a few parts per thousand of the aluminium ions are replaced by chromium(III) ions - the chromium atoms are surrounded by six oxygen atoms. This leads to the chromium atoms strongly absorbing light in the violet and yellow-green regions. We see this as mainly red with some bluegivingin the best casesthe characteristic pigeon-blood colour of the finest rubies. Meera Senthilingam Christopher Blanford explains the sparkling and colourful chemistry of chromium in next week's Chemistry in its Element. Until then I'm Meera Senthilingam from the nakedscientists.com and thank you for listening. (Promo) Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com. There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements. (End promo)
|
Resources
Learn Chemistry: Your single route to hundreds of free-to-access chemistry teaching resources.
Visual Elements images and videos
© Murray Robertson 1998-2017.
W. M. Haynesed. CRC Handbook of Chemistry and PhysicsCRC Press/Taylor and FrancisBoca RatonFL95th EditionInternet Version 2015accessed December 2014.
Tables of Physical & Chemical ConstantsKaye & Laby Online16th edition1995. Version 1.0 (2005)accessed December 2014.
J. S. CourseyD. J. SchwabJ. J. Tsaiand R. A. DragosetAtomic Weights and Isotopic Compositions (version 4.1)2015National Institute of Standards and TechnologyGaithersburgMDaccessed November 2016.
T. L. Cottrell, The Strengths of Chemical BondsButterworthLondon1954.
John Emsley, Nature’s Building Blocks: An A-Z Guide to the ElementsOxford University PressNew York2nd Edition2011.
Thomas Jefferson National Accelerator Facility - Office of Science EducationIt’s Elemental - The Periodic Table of Elementsaccessed December 2014.
Periodic Table of Videosaccessed December 2014.
Derived in part from material provided by the British Geological Survey © NERC.
Elements 1-112114116 and 117 © John Emsley 2012. Elements 113115117 and 118 © Royal Society of Chemistry 2017.
Produced by The Naked Scientists.
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
© Murray Robertson 1998-2017.
Data
W. M. Haynesed. CRC Handbook of Chemistry and PhysicsCRC Press/Taylor and FrancisBoca RatonFL95th EditionInternet Version 2015accessed December 2014.
Tables of Physical & Chemical ConstantsKaye & Laby Online16th edition1995. Version 1.0 (2005)accessed December 2014.
J. S. CourseyD. J. SchwabJ. J. Tsaiand R. A. DragosetAtomic Weights and Isotopic Compositions (version 4.1)2015National Institute of Standards and TechnologyGaithersburgMDaccessed November 2016.
T. L. Cottrell, The Strengths of Chemical BondsButterworthLondon1954.
Uses and properties
John Emsley, Nature’s Building Blocks: An A-Z Guide to the ElementsOxford University PressNew York2nd Edition2011.
Thomas Jefferson National Accelerator Facility - Office of Science EducationIt’s Elemental - The Periodic Table of Elementsaccessed December 2014.
Periodic Table of Videosaccessed December 2014.
Supply risk data
Derived in part from material provided by the British Geological Survey © NERC.
History text
Elements 1-112114116 and 117 © John Emsley 2012. Elements 113115117 and 118 © Royal Society of Chemistry 2017.
Podcasts
Produced by The Naked Scientists.
Periodic Table of Videos
Created by video journalist Brady Haran working with chemists at The University of Nottingham.
