Titanium (Ti)

Roughly 95% of all titanium mined never becomes metal — it is turned into titanium dioxide, the pigment that makes white paint white, toothpaste opaque and mineral sunscreen work. The metal is as strong as many steels at 45% less weight, but it is expensive because reducing the ore is awkward: the Kroll process is a batch operation that has not fundamentally changed since 1940. Titanium is uniquely tolerated by the body, and bone grows directly onto its oxide surface rather than walling it off, which is what makes dental implants possible.

Properties

Atomic number

22

Symbol

Ti

Standard atomic weight

47.867 u

Category

Transition metal

Group

4

Period

4

Block

d-block

Electron configuration

[Ar] 4s² 3d²

Electrons per shell

2, 8, 10, 2

Melting point

1,941 K — 1667.8 °C — 3034.1 °F

Boiling point

3,560 K — 3286.8 °C — 5948.3 °F

Density

4.5 g/cm³

Electronegativity

1.54 (Pauling)

Oxidation states

+4, +3, +2

Discovered

1791 by William Gregor

Electron configuration

Full

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d²

Noble gas shorthand

[Ar] 4s² 3d²

Shells

K: 2 · L: 8 · M: 10 · N: 2

What it is used for

• Jet engine fan blades and compressor discs
• Hip and dental implants, which bone will bond to directly
• Titanium dioxide as the white pigment in paint, paper and sunscreen
• Marine hardware and desalination plant, for seawater resistance
• Spectacle frames, watch cases and bicycle frames

Neighbours in the table

Group 4

Elements in the same group share their outer electron count, which is why they behave similarly in reactions. Titanium sits in group 4 with zirconium, hafnium, rutherfordium.