More Facts About Titanium
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Atomic Number: |
22 |
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Atomic Radius: |
144.8 pm |
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Atomic Symbol: |
Ti |
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Melting Point: |
1668 șC |
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Atomic Weight: |
47.90 |
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Boiling Point: |
3287 șC |
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Electron Configuration: |
[Ar]4s23d2 |
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Oxidation
States: |
4,3,2 |
History
(Latin. titans, the first sons of the Earth, mythology)
Discovered by Gregor in 1791; named by Klaproth in 1795.
Impure titanium was prepared by Nilson and Pettersson in 1887;
however, the pure metal (99.9%) was not made until 1910 when
Hunter heated TiCl4
with sodium in a steel bomb.
Sources
Titanium is present in meteorites and the sun. Rocks obtained
during the Apollo 17 lunar mission showed presence of 12.1%
TiO2; rocks obtained during earlier Apollo
missions show lower percentages.
Titanium oxide bands are prominent in the spectra of M-type
stars. The element is the ninth most abundant in the crust
of the earth. Titanium is almost always present in igneous
rocks and in the sediments derived from them.
It occurs in the minerals rutile, ilmenite, and sphene, and
is present in titanates and in many iron ores. Titanium is
present in ash of coal, in plants, and in human body.
The metal was a laboratory curiosity until Kroll, in 1946,
showed that titanium could be produced commercially by reducing
titanium tetrachloride with magnesium. This method is still
largely used for producing the metal. The metal can be purified
by decomposing the iodide.
Properties
Titanium, when pure, is a lustrous, white metal. It has a
low density, good strength, is easily fabricated, and has
excellent corrosion resistance. It is ductile only when it
is free of oxygen. The metal, which burns in air, is the only
element that burns in nitrogen.
Titanium is resistant to dilute sulfuric and hydrochloric
acid, most organic acids, most chlorine gas, and chloride
solutions.
Natural titanium is reported to become very radioactive after
bombardment with deuterons. The emitted radiations are mostly
positrons and hard gamma rays. The metal is dimorphic. The
hexagonal alpha form changes to the cubic beta form very slowly
at about 880oC.
The metal combines with oxygen at red heat, and with chlorine
at 550oC.
Titanium metal is considered to be physiologically inert.
When pure, titanium dioxide is relatively clear and has an
extremely high index of refraction with an optical dispersion
higher than diamond.
Isotopes
Natural titanium consists of five isotopes with atomic masses
from 46 to 50. All are stable. Eight other unstable isotopes
are known.
Uses
Titanium is important as an alloying agent with aluminum,
molybdenum, manganese, iron, and other metals. Alloys of titanium
are principally used for aircraft and missiles where lightweight
strength and ability to withstand extremes of temperature
are important.
Titanium is as strong as steel, but 45% lighter. It is 60%
heavier than aluminum, but twice as strong.
Titanium has potential use in desalination plants for converting
sea water into fresh water. The metal has excellent resistance
to sea water and is used for propeller shafts, rigging, and
other parts of ships exposed to salt water. A titanium anode
coated with platinum has been used to provide cathodic protection
from corrosion by salt water.
It is produced artificially for use as a gemstone, but it
is relatively soft. Star sapphires and rubies exhibit their
asterism as a result of the presence of TiO2.
Titanium dioxide is extensively used for both house paint
and artist's paint, because it is permanent and has good covering
power. Titanium oxide pigment accounts for the largest use
of the element. Titanium paint is an excellent reflector of
infrared, and is extensively used in solar observatories where
heat causes poor viewing conditions.
Titanium tetrachloride is used to iridize glass. This compound
fumes strongly in air and has been used to produce smoke screens.
Costs
The price of titanium metal powder varies.
Sources: CRC
Handbook of Chemistry and Physics and the American
Chemical Society.
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