Quick Facts
| Property | Value |
|---|---|
| Symbol | Sn |
| Atomic Number | 50 |
| Atomic Mass | 118.71 u |
| Category | Post-Transition Metal |
| Period | 5 |
| Group | 14 |
| Block | p |
| Electron Configuration | [Kr] 4d¹⁰ 5s² 5p² |
Physical Properties
| Property | Value |
|---|---|
| State at 20°C | Solid |
| Density | 7.365 g/cm³ (white tin) |
| Melting Point | 231.93°C (505.08 K) |
| Boiling Point | 2602°C (2875 K) |
| Appearance | Silvery-white, soft metal |
Atomic Properties
| Property | Value |
|---|---|
| Electron Configuration | [Kr] 4d¹⁰ 5s² 5p² |
| Electronegativity | 1.96 (Pauling scale) |
| First Ionization Energy | 708.6 kJ/mol |
| Atomic Radius | 140 pm |
| Covalent Radius | 139 pm |
| Van der Waals Radius | 217 pm |
History and Discovery
Discovered by: Known since antiquity Year of Discovery: ~3500 BCE Location: Ancient Middle East
Etymology
The symbol "Sn" comes from Latin "stannum." The English "tin" is of Germanic origin. The Bronze Age began when humans learned to alloy tin with copper.
Discovery Story
Tin has been known since ancient times. It was essential for making bronze (copper-tin alloy), which defined the Bronze Age. Ancient Phoenicians traded tin from Cornwall, England, and other sources. The earliest tin artifacts date to around 3500 BCE.
Isotopes
| Isotope | Natural Abundance | Half-life | Decay Mode |
|---|---|---|---|
| ¹¹²Sn | 0.97% | Stable | - |
| ¹¹⁴Sn | 0.66% | Stable | - |
| ¹¹⁵Sn | 0.34% | Stable | - |
| ¹¹⁶Sn | 14.54% | Stable | - |
| ¹¹⁷Sn | 7.68% | Stable | - |
| ¹¹⁸Sn | 24.22% | Stable | - |
| ¹¹⁹Sn | 8.59% | Stable | - |
| ¹²⁰Sn | 32.58% | Stable | - |
| ¹²²Sn | 4.63% | Stable | - |
| ¹²⁴Sn | 5.79% | Stable | - |
Occurrence
Natural Abundance
Tin comprises about 2.3 ppm of Earth's crust. The main ore is cassiterite (SnO₂). Major producers are China, Indonesia, Myanmar, and Peru.
Extraction and Production
- Smelting: Reduction of cassiterite with carbon
- Sources: Cassiterite mining (alluvial and hard-rock)
- Global production: about 300,000 tons annually
Applications and Uses
Tinplate and Coatings
- Tinplate for food cans
- Corrosion-resistant coatings
- Electroplating
Alloys
- Bronze (copper-tin)
- Pewter (tin-antimony-copper)
- Solder (declining lead use)
- Babbitt metal (bearings)
Electronics
- Lead-free solders
- Tin whiskers (a problem in electronics)
Other Uses
- Glass manufacturing (float glass process)
- Tin oxide for glass coatings
- Tin chemicals (stabilizers, catalysts)
- Dental amalgams
Biological Role
Tin has no established essential role in humans, though some researchers suggest it may be needed in trace amounts.
In the Human Body
- About 30 mg present in adult body
- No confirmed essential function
- Poorly absorbed from food
Toxicity
Inorganic tin has low toxicity. Organotin compounds (TBT) are toxic.
Safety and Hazards
Toxicity
Metallic tin and most inorganic compounds are non-toxic. Organotin compounds (tributyltin, TBT) are highly toxic.
Handling Precautions
- Generally safe to handle
- Organotin compounds require careful handling
- Tin pest (transformation to gray tin) can occur below 13°C
Environmental Impact
Tributyltin (TBT) antifouling paints caused severe marine pollution. Now banned for most uses. Tin mining can affect local environments.
Interesting Facts
- Tin has the most stable isotopes of any element (ten)
- Tin pest caused buttons on Napoleon's soldiers' uniforms to crumble in the Russian cold
- "Tin cans" are actually mostly steel with a thin tin coating
- The characteristic "tin cry" sound occurs when tin is bent
- Tin was essential for the Bronze Age, which started around 3300 BCE