Atomic Number: 22
Atomic Symbol: Ti
Atomic Weight: 47.867
Melting Point: 3,034 F (1,668 C) |
Boiling Point: 5,949 F (3,287 C)
Word origin: The word titanium comes from the Latin titans (the first sons of Earth in Greek mythology).
Discovery: Titanium was discovered by William Gregor in 1791 and named by Martin Heinrich Klaproth in 1795. It was first prepared in an impure form in 1887 but it was not prepared as a pure metal until 1910 when Matthew A. Hunter heated titanium tetrachloride (TiCl4) with sodium in a steel bomb.
Properties of titanium
Titanium is classified as a transitional metal. Pure titanium is a lustrous white metal. It is strong, light with low density, and has excellent corrosion resistance. Titanium is as strong as steel but 45 percent lighter. It is 60 percent heavier than aluminum, but twice as strong. [See Periodic Table of the Elements]
It is ductile only when free of oxygen. Titanium metal is the only element that burns in nitrogen; it burns in air. It is considered to be physiologically inert. It is dimorphic; the hexagonal alpha form changes to the cubic beta form very slowly at a temperature of about 880 C (1,616 F).
The metal combines with oxygen at red heat and with chlorine at 550 C (1,022 F). Titanium is resistant to dilute sulfuric and hydrochloric acid, most organic acids, most chlorine gas and chloride solutions.
Titanium dioxide, when pure, is relatively clear and has an extremely high refraction index with optical dispersion greater than a diamond.
Natural titanium becomes highly radioactive after being bombarded with deuterons. The emitted radiations are mostly positrons and hard gamma-rays. Natural titanium consists of five isotopes. They have atomic masses from 46 to 50 and all are stable. There are eight other known isotopes of titanium.
Sources of titanium
Titanium is found in space and on Earth. It is present in meteorites, the sun, and M-type stars. Rocks from Apollo lunar missions showed the presence of titanium.
Titanium is the ninth most abundant element in Earth’s crust. It is almost always present in igneous rocks and their sediments. Titanium also occurs in:
- The minerals rutile, ilmenite and sphene
- Titanates and in many iron ores
- The ash of coal
- The human body
It was unknown how to manufacture titanium until 1946 when William J. Kroll reduced titanium tetrachloride with magnesium. Kroll’s method is still largely used to produce titanium. The metal is purified by decomposing the iodide.
Uses of titanium
Due to its impressive strength and light weight, titanium is an important alloying agent with aluminum, molybdenum, manganese, iron and other metals. These alloys are used for aircraft, missiles and other products that require lightweight strength and/or the ability to withstand extreme temperatures.
Artificially produced titanium can be used as a gemstone despite its relative softness. The presence of titanium dioxide (TiO2) in star sapphires and rubies causes their asterism.
The metal has excellent resistance to seawater and is used in propeller shafts, rigging and other parts of ships that are exposed to salt water. A titanium anode coated with platinum has been used to provide cathodic protection from corrosion by salt water. Because of its resistance to salt water, titanium could be helpful in desalinization plants.
Titanium tetrachloride is used to iridize glass. Since the compound smells strongly in air, it has been used to produce smoke screens.
(Source: Los Alamos National Laboratory)