Titanium
Atomic Data
| Atomic Number | 22 |
| Symbol | Ti |
| Atomic Weight | 47.867 u |
| Density (STP) | 4.506 g/cm³ |
| Melting Point | 1667.85 °C (1941 K) |
| Boiling Point | 3286.85 °C (3560 K) |
| Electronegativity | 1.54 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d2 4s2 |
| Oxidation States | +2, +3, +4 |
| Phase at STP | Solid |
| Category | Transition Metal |
| Period / Group | 4 / 4 |
| CAS Number | 7440-32-6 |
Electron Configuration
[Ar] 3d2 4s2
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 2 | 20 |
| N | 4 | 4s | 2 | 22 |
| Total | 22 | 22 | ||
Isotopes of Titanium
Titanium has five naturally occurring stable isotopes. The most abundant is ⁴⁸Ti, comprising 73.72% of all naturally occurring Titanium.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Titanium-46 | ⁴⁶Ti | 22 | 24 | 8.25 | Stable |
| Titanium-47 | ⁴⁷Ti | 22 | 25 | 7.44 | Stable |
| Titanium-48 | ⁴⁸Ti | 22 | 26 | 73.72 | Stable |
| Titanium-49 | ⁴⁹Ti | 22 | 27 | 5.41 | Stable |
| Titanium-50 | ⁵⁰Ti | 22 | 28 | 5.18 | Stable |
Abundance & Occurrence
Titanium is present in Earth's crust at approximately 5650 ppm by mass and at approximately 3 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Universe (ppm by mass)
Discovery & History
Read more about the discovery of the periodic table of elements →
Safety & Handling
- Fire and dust explosion: Titanium powder and fine turnings are highly flammable and can ignite spontaneously in air; titanium fires are very difficult to extinguish and require dry sand or Class D agents: water, CO2, and halon must not be used.
- Machining hazards: Titanium generates fine flammable chips and dust during machining; coolant must be applied continuously to prevent heat build-up, and swarf bins must not be allowed to accumulate dry chips.
- Titanium tetrachloride (TiCl4): This industrial precursor reacts violently with water and moist air, producing HCl fumes; it is severely corrosive and must be handled in dry, ventilated conditions.
- Bulk metal: Bulk titanium metal has low toxicity and is biocompatible (used in implants and surgical instruments); hazards are largely physical (dust/fire) rather than toxic.
Titanium in the Real World
Real-World Uses
- Aerospace structures: Titanium alloys (Ti-6Al-4V) offer the best strength-to-density ratio of any structural metal at temperatures up to 600 °C, used in aircraft fuselage frames, engine fan blades, and landing gear.
- Biomedical implants: Titanium's biocompatibility and osseointegration ability make it the preferred material for hip and knee replacement components, dental implants, spinal fixation hardware, and surgical instruments.
- White pigment: Titanium dioxide (TiO₂) is the world's most used white pigment, present in over 95% of white paints and coatings, as well as in white plastics, paper, sunscreen, and food colouring.
- Chemical plant equipment: Titanium's exceptional corrosion resistance in chloride solutions, seawater, and oxidising acids makes it the material of choice for heat exchangers, reactors, and piping in chemical, marine, and desalination plants.
- Consumer goods and sports equipment: Lightweight titanium frames are used in high-end bicycles, golf clubs, eyeglass frames, watchcases, and camping equipment where weight reduction justifies the higher material cost.
Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.
Frequently Asked Questions
What is titanium used for?
Titanium is used extensively in aerospace engineering for airframes and jet engine components because it combines high strength with low density and excellent corrosion resistance. It is also the material of choice for medical implants such as joint replacements and dental implants, since the human body tolerates it exceptionally well.
Is titanium toxic?
Titanium metal and most of its compounds are considered non-toxic and biologically inert. This biocompatibility is why titanium is widely used in surgical implants. Titanium dioxide (TiO2), used as a white pigment, is also considered safe for use in foods and cosmetics at regulated levels.
How was titanium discovered?
Titanium was discovered in 1791 by British amateur mineralogist William Gregor, who found an unknown oxide in the mineral ilmenite. German chemist Martin Heinrich Klaproth independently identified it in 1795 and named it after the Titans of Greek mythology. Pure metallic titanium was not produced until 1910.
Why is titanium so corrosion-resistant?
When exposed to oxygen, titanium instantly forms a thin, stable layer of titanium dioxide on its surface. This passive oxide layer is self-healing: if scratched, it re-forms in milliseconds: and prevents further oxidation even in saltwater and many acids.