Titanium Ti

Discovery

In 1791 the English clergyman and amateur mineralogist William Gregor examined a black, magnetic sand from a stream in the parish of Manaccan in Cornwall. He found that it contained iron and the oxide of an unknown metal, and he named the mineral menachanite, now known as ilmenite.

A few years later, in 1795, the German chemist Martin Heinrich Klaproth independently found the same oxide in the mineral rutile from Hungary. He recognised it as a new element, gave it the name titanium, and later confirmed that Gregor's metal was the same.

Pure titanium proved very difficult to make because the hot metal combines with oxygen, nitrogen and carbon. In 1910 Matthew Hunter in the United States produced nearly pure titanium by heating titanium tetrachloride with sodium. The Kroll process, developed by William Kroll in the 1930s and 1940s using magnesium instead, made large-scale production possible and is still the main method today.

Origin of the name

Klaproth named the element after the Titans, the powerful sons of the Earth goddess in Greek mythology, following the example of uranium, which he had named after the planet Uranus. The symbol is Ti.

Main uses

• Pigment: most titanium ore is turned into titanium dioxide, a brilliant white pigment used in paints, paper, plastics and cosmetics.
• Aerospace: titanium alloys such as Ti-6Al-4V are used in jet engines, airframes and spacecraft.
• Medicine: titanium is biocompatible and bonds with bone, so it is used for hip and knee replacements, dental implants and bone plates.
• Chemical industry and seawater: its resistance to corrosion suits heat exchangers, desalination plants and offshore equipment.
• Consumer goods: bicycle frames, golf clubs, watches, eyeglass frames and jewellery.

Isotopes

Titanium has five stable isotopes, titanium-46 through titanium-50, of which titanium-48 is the most common at about 74 percent. The radioactive titanium-44, with a half-life of about 60 years, is produced in supernova explosions; gamma rays from its decay have been detected in the remnant Cassiopeia A, giving astronomers direct evidence of how such explosions forge new elements.

In everyday life

Titanium metal is non-toxic, which is why it is widely used inside the body and in jewellery for people with metal allergies. Titanium dioxide is found in white paint, sunscreens and toothpaste. Its use as a food colouring was banned in the European Union in 2022 as a precaution, though it remains permitted in some other countries.

Fine titanium powder can burn, but solid titanium is very safe to handle.