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|OTP appearance||grey solid|
|Coefficient of Thermal Expansion(×10-6 °C-1)||23.8|
- as a component of bronze, brass and pewter.
- as a component of solder
- tin is a useful structural material where its malleable nature is used, such as hinges or crimpable fasteners
- Elemental tin does not occur naturally
- -oxide occurrs naturally as cassiterite
- Virtually all organotin compounds are highly toxic
- At temperatures below 14°C, tin undergoes an allotropic change which changes the tin from a metallic form to a nonmetallic form. This is called "tin blight" or "tin pest". This process slowly reverses above 14°C and is rapidly reversed above 100°C.
- Tin has two important allotropes:
- α- or "grey" tin which is grey, brittle, and nonmetallic.
- β- or "white" tin which is silvery, ductile and metallic.
- At 13.2 °C and below, pure Β tin transforms to α-tin
- At 100°C and above α-tin reverts to Β-tin.
- Carbothermic reduction of cassiterite
Reduction of tin with carbon is not an easy process since the free energies of reduction are unfavorable.
- SnO2 + C → Sn + CO2ΔH=+125.2 kJ
However, reduction with carbon monoxide is considerably less unfavorable. For the reaction
- SnO2 + CO → SnO + CO2ΔH=+5.5 kJ // First oxygen
- SnO + CO → Sn + CO2ΔH=-0.3 kJ // Second oxygen
- SnO2 + 2 CO → 2 CO2 + SnΔH=+5.2kJ // Net
- stacked as ingots, keeping the temperature above 14°C
- Smelting Tin at Geevor Museum
- An Analysis of the Process of Smelting Tin, The Bulletin of Peak District Mines Historical Society Vol 13 No 2 Winter 1996