Titanium (Ti)

Titanium (symbol Ti) is the chemical element with atomic number 22: a transition metal, solid at 0 °C, with an atomic mass of 47.867 u. Discovered in 1791 (William Gregor).

Titanium is as strong as many steels while being about 45% lighter. It doesn't rust and barely corrodes, even in seawater. The human body tolerates it so well that it fuses with bone, hence its use in implants. Yet most of its production ends up as titanium dioxide, the white pigment in paints.

Key facts

Atomic number: 22
Symbol: Ti
French name: Titane
Atomic mass: 47.867 u
Molar mass: 47.867 g/mol
Family: Transition metals
Position: period 4, group 4, d-block
State at 0 °C: Solid
Melting point: 1,667.9 °C
Boiling point: 3,286.9 °C
Density: 4.51 g/cm³
Electronegativity (Pauling): 1.54
First ionization energy: 659 kJ/mol
Atomic radius: 140 pm
Electron configuration: [Ar] 3d² 4s²
Abundance in Earth's crust: 5,650 ppm (9th most abundant element)
Indicative price: 11 $/kg (order of magnitude)
Radioactive: no
Discovery: 1791, William Gregor

Origin of the name

From the Titans of Greek mythology.

What does titanium look like?

A shiny, silvery-gray metal that can take on iridescent colors (blue, purple, gold) when its oxide layer is thickened.

Where is titanium found?

About 0.56% of Earth's crust, the ninth most abundant element. It is found in almost every rock, and concentrated in black beach sands rich in ilmenite and rutile.

Natural sources

Ilmenite
Rutile
Anatase
Leucoxene

How is titanium produced?

The ore is converted to titanium tetrachloride, then reduced with molten magnesium (Kroll process) to form a titanium “sponge” that is remelted. This slow, costly process explains the metal's high price. About 90% of the ore, however, goes into making titanium dioxide pigment.

Top producers

China
Mozambique
South Africa
Australia
Canada

What is titanium used for?

White pigment in paints, plastics and paper.
Aircraft and jet engine parts.
Dental implants, hip replacements and surgical screws.
Chemical equipment and desalination plants.
Watches, eyeglasses, bike frames.
Mineral sunscreens.

In everyday life

White wall paint
Dental implants
“Mineral” sunscreen
Lightweight eyeglass frames

Role in living things

No known biological role. It is remarkably well tolerated: bone bonds directly to its surface, a phenomenon called osseointegration, discovered by chance by the Swede Per-Ingvar Brånemark in the 1950s.

Hazards of titanium

The solid metal is inert and non-toxic. Fine powder is flammable. Inhaled fine particles of titanium dioxide are classified as a possible carcinogen; its use as a food coloring (E171) has been banned in the European Union since 2022, after France banned it in 2020.

Cosmic origin

Supernovae: Forged in the cores of massive stars, then scattered when they explode.
White dwarfs: Produced by the thermonuclear explosion of a white dwarf (type Ia supernova).

History of titanium

In 1791, English clergyman William Gregor found an unknown metal in a black sand from Cornwall. In 1795, the German Martin Heinrich Klaproth found it again in rutile and named it after the Titans of Greek mythology. The pure metal was not obtained until 1910, and the industry was born after the Kroll process, in the 1940s.

Did you know?

The American SR-71 Blackbird spy plane was more than 90% titanium, some of it bought from the USSR through front companies.
The Guggenheim Museum in Bilbao is clad in about 33,000 very thin titanium panels.
Pure titanium doesn't melt until 1,668 °C.

Isotopes of titanium

Five stable isotopes, with titanium-48 accounting for nearly three quarters. Radioactive titanium-44 has been spotted in supernova remnants such as Cassiopeia A.

titanium-44: radioactive, half-life 59.1 years. Generator of scandium-44 for PET; its gamma rays trace supernova explosions.
titanium-46: 8.25% of natural titanium, stable
titanium-47: 7.44% of natural titanium, stable
titanium-48: 73.72% of natural titanium, stable
titanium-49: 5.41% of natural titanium, stable
titanium-50: 5.18% of natural titanium, stable

Common compounds

Titanium dioxide (TiO₂)

Related elements

Same family (transition metals): Scandium (Sc), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), Yttrium (Y), Zirconium (Zr), Niobium (Nb), Molybdenum (Mo), Technetium (Tc), Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Silver (Ag), Cadmium (Cd), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt), Gold (Au), Mercury (Hg), Rutherfordium (Rf), Dubnium (Db), Seaborgium (Sg), Bohrium (Bh), Hassium (Hs).

Same column (group 4): Zirconium (Zr), Hafnium (Hf), Rutherfordium (Rf).