Titanium Chemical & Physical Properties

bar of high-purity titanium crystals
Alchemist-hp

Titanium is a strong metal used in human implants, aircraft, and many other products. Here are facts about this useful element:

Basic Facts

Isotopes

There are 26 known isotopes of titanium ranging from Ti-38 to Ti-63. Titanium has five stable isotopes with atomic masses 46-50. The most abundant isotope is Ti-48, accounting for 73.8% of all natural titanium.

Properties

Titanium has a melting point of 1660 +/- 10°C, boiling point of 3287°C, specific gravity of 4.54, with a valence of 2, 3, or 4. Pure titanium is a lustrous white metal with low density, high strength, and high corrosion resistance. It is resistant to dilute sulfuric and hydrochloric acids, moist chlorine gas, most organic acids, and chloride solutions. Titanium is only ductile when it is free of oxygen. Titanium burns in air and is the only element that burns in nitrogen.

Titanium is dimorphic, with the hexagonal a form slowly changing to the cubic b form around 880°C. The metal combines with oxygen at red heat temperatures and with chlorine at 550°C. Titanium is as strong as steel, but it is 45% lighter. The metal is 60% heavier than aluminum, but it is twice as strong.

Titanium metal is considered to be physiologically inert. Pure titanium dioxide is reasonably clear, with an extremely high index of refraction and an optical dispersion higher than that of a diamond. Natural titanium becomes highly radioactive upon bombardment with deuterons.

Uses

Titanium is important for alloying with aluminum, molybdenum, iron, manganese, and other metals. Titanium alloys are used in situations where lightweight strength and ability to withstand temperature extremes are required (e.g., aerospace applications). Titanium may be used in desalination plants. The metal is frequently used for components which must be exposed to seawater. A titanium anode coated with platinum may be used to provide cathodic corrosion protection from seawater.

Because it is inert in the body, titanium metal has surgical applications. Titanium dioxide is used to make man-made gemstones, although the resulting stone is relatively soft. The asterism of star sapphires and rubies is a result of the presence of TiO2. Titanium dioxide is used in house paint and artist paint. The paint is permanent and provides good coverage. It is an excellent reflector of infrared radiation. The paint is also used in solar observatories.

Titanium oxide pigments account for the largest use of the element. Titanium oxide is used in some cosmetics to disperse light. Titanium tetrachloride is used to iridize glass. Since the compound fumes strongly in air, it is also used to produce smoke screens.

Sources

Titanium is the 9th most abundant element in the earth's crust. It is almost always found in igneous rocks. It occurs in rutile, ilmenite, sphene, and many iron ores and titanates. Titanium is found in coal ash, plants, and in the human body. Titanium is found in the sun and in meteorites. Rocks from the Apollo 17 mission to the moon contained up to 12.1% TiO2. Rocks from earlier missions showed lower percentages of titanium dioxide. Titanium oxide bands are seen in spectra of M-type stars. In 1946, Kroll showed that titanium could be produced commercially by reducing titanium tetrachloride with magnesium.

Physical Data

Trivia

  • Titanium was discovered in a black sand known as ilmenite. Ilmenite is a mixture of iron oxides and titanium oxides.
  • William Gregor was the pastor of Mannacan parish when he discovered titanium. He named his new metal 'manaccanite'.
  • The German chemist Martin Klaproth rediscovered Gregor's new metal and named it titanium after the Titans, Greek mythological beings of the Earth. The name 'titanium' was preferred and ultimately adopted by other chemists but acknowledged Gregor as the original discoverer.
  • Pure titanium metal was not isolated until 1910 by Matthew Hunter--119 years after its discovery.
  • Approximately 95% of all titanium is used in the production of titanium dioxide, TiO2. Titanium dioxide is an extremely bright white pigment used in paints, plastics, toothpaste, and paper.
  • Titanium is used in medical procedures because it is non-toxic and non-reactive in the body.

References

  • Los Alamos National Laboratory (2001)
  • Crescent Chemical Company (2001)
  • Lange's Handbook of Chemistry (1952)
  • CRC Handbook of Chemistry & Physics (18th Ed.)
  • International Atomic Energy Agency ENSDF database (Oct 2010)