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Titanium

Atomic Number: 22
Symbol: Ti
Atomic Weight: 47.88
Discovery: William Gregor 1791 (England)
Electron Configuration: [Ar] 4s² 3d²
Word Origin: Latin titans: in mythology, the first sons of Earth
Isotopes: There are 13 known isotopes of titanium. Natural titanium includes five stable isotopes with atomic masses 46-50.

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 hgher than that of 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 present 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.

Element Classification: Transition Metal
Density (g/cc): 4.54
Melting Point (K): 1933
Boiling Point (K): 3560
Appearance: Shiny, dark-gray metal
Atomic Radius (pm): 147
Atomic Volume (cc/mol): 10.6
Covalent Radius (pm): 132
Ionic Radius: 68 (+4e) 94 (+2e)
Specific Heat (@20°C J/g mol): 0.523
Fusion Heat (kJ/mol): 18.8
Evaporation Heat (kJ/mol): 422.6
Debye Temperature (K): 380.00
Pauling Negativity Number: 1.54
First Ionizing Energy (kJ/mol): 657.8
Oxidation States: 4, 3
Lattice Structure: 1.588
Lattice Constant (Å): 2.950
References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)