Tin and its alloys are some of the oldest metals known to man. In the year 2007, 320 thousand metric tonnes of tin were mined.

Physical properties: Tin is a soft silvery-white metal. It is malleable at room temperature, but it turns brittle when it is cooled. Tin is quite dense (7.37 gram/cm3) and very soft (1.5 on a 10 point scale). Below 13C, pure tin turns into a gray powder that hardly looks and acts like a metal. Tin melts at a relatively low temperature of 232C, and boils at 2602C. Due to its low melting point, tin cannot not used in places that can get very hot. Bending a bar of tin produces a sound called a "tin cry" as the crystals within are stressed. When alloyed with other metals, tin often makes the alloy more hard and brittle.

Chemical properties: Tin does not react with air or water (including sea-water) at room temperature but it is easily attacked by acids and alkalis. As it is unaffected by air and water in the environment, tin is used to coat other metals and protect them from rusting.

History: Tin has been known since the early days of man. One of the pre-historic uses of tin was to make bronze. Bronze is mostly copper with a small amount of tin, but it is much harder than copper. Tin was also used to make other alloys such as pewter. A shipwreck near Turkey dating back to 1336 BC has been found carrying a shipment of tin that probably originated from Afghanistan. Another shipwreck from 1750 BC was also found carrying tin ingots. The shipwrecks point to a thriving tin trade in the Mediterranean that brought the metal to Europe. European tin mining is thought to have begun in Cornwall and Devon. Some believe the Romans invaded Britain mainly to secure their supply of tin.

More recently, it was said that that during Napoleon's Russian campaign in 1812, the winter air became so cold that the tin buttons on Napoleon's soldiers' uniforms disintegrated. This apparently contributed in part to the defeat of the Grande Armée. Today the word tin is used to describe any sheet metal, and cans and other containers are sometimes called "tins". The Ford Model T automobile was coated with tin to protect it against rusting, which earned it the name "Tin Lizzy".

Production: In the Medieval times Cornwall was the major tin producer. Over time, the center of tin production shifted to Bolivia, and finally to East Asia (China and Malaysia). Tin is extracted mostly from its oxide cassiterite, deposits of which are found mostly near river beds. Tin is extracted from the oxide by heating the ore with coal. The carbon in coal combines with the oxygen of the oxide to form carbon dioxide, leaving pure tin. Some tin is also produced by recycling scrap metal. The top five producers of tin today are China, Indonesia, Peru, Bolivia and Brazil. Pie Chart of Top 5 Tin Producing Countries...

Uses: Tin is used by itself, and in a wide variety of alloys. The heaviest use of tin is in solder that joins other metal components such as pipes and electric circuits. Solder used to be mostly tin and lead, but the ban on lead (because of its health effects) has started a search for some other metal to mix with tin to make solder. Tin is also used to coat metals like iron and steel to prevent them from rusting. Tin-plated steel is used widely to make food containers. This is why people call some containers "tin cans" or just "tins". The alloy of tin and copper, bronze, is now used mostly to make sculptures, though it was earlier used to make cannons. Another alloy, pewter (mostly tin, with a little copper or lead), is also used nowadays mainly to make decorative objects.

Health: As far as scientists know, tin plays no important part in the human body, and is not toxic. However most tin salts are toxic. Some tin compounds are used to kill bacteria and fungi.

References

Gray, Leon. Tin : The Elements, 2003, Marshall Cavendish, USA.

Tin, Wikipedia. <http://en.wikipedia.org/wiki/Tin> accessed on 20-Feb-2009.