History and Production
Derived from the Latin name titan, the first sons of the Earth. The oxide was first discovered by a vicar named W. Gregor in 1791, extracted from ilmenite. The impure oxide was also independantly discovered by M.H. Klaproth from rutile ore and subsequently named the
element titanium. The metal production became commercially viable only after it was discovered that titanium tetrachloride can be reduced with calcium, discovered by W. Kroll in 1932. Today, magnesium is usually used in the reduction process. It is important as an alloying agent
with aluminium, molybdenum, iron and other metals. These alloys are usually used in aircraft and missile construction where lightweight and ability to withstand extreme conditions are essential. Due to its resistance to corrosion, it is also used for propeller shafts and other parts of ship that exposes to sea water.
Titanium dioxide is used as paint and pigment.
Titanium is a lustrous white metal. It has a low density, good strength and resistant to corrosion. It is ductile in the absence of oxygen and is the only element that burns in nitrogen. The metal is dimorphic where the hexagonal alpha form changes to the cubic beta form slowly at around 882°C. It is found in wide abundance (about 6320 ppm) in the earth's crust. The
most important minerals being ilmenite (FeTiO3) and rutile (TiO2).
Interatomic distance: 289.6 pm
Melting point: 1668°C
Boiling point: 3287°C
Thermal conductivity/Wm-1K-1: 21.9 (27°C)
Density/kgm-3: 4540 (20°C)
Standard Thermodynamic Data (atomic gas)
Enthalpy of formation: 473 kJ/mol
Gibbs free energy of formation: 428.4 kJ/mol
Entropy: 180.3 J/mol K
Heat capacity: 24.4 J/mol K
Electronic configuration: [Ar] 3d2 4s2
Term symbol: 3F2
Electron affinity: 7.6223 kJ/mol Electronegativity (Pauline): 1.54
Ionization energy (first, second, third): 658.812, 1309.84, 2652.55 kJ/mol
Titanium has high resistance to corrosion and attackes of acids and alkalis. However, it absorbs hydrogen easily and is attacked rapidly by chlorine at room temperature.
Titanium reacts with nitrogen at 800°C to give the nitride, TiN. Hence extraction of titanium must be carried out in an inert atmosphere
(such as argon) in the reduction process.
Titanium compounds in solution are oxidized by hydrogen peroxide to give peroxytitanates. These are colored red or orange and the appearance
of this color constitute a test for titanium.