Tin derives its chemical symbol (Sn) from the Latin word stannum. The first uses of tin appear to have been in alloys with copper and zinc to make brass and bronze respectively, and can be dated back to about 3,500 BC. It is not known who identified tin as an element. It may have been recognized as something that could not be divided any further by alchemists and experimenters.
Tin is a silvery white metal, is malleable, somewhat ductile and has a highly crystalline structure. If tin is bent, the breaking of these crystals will emit an audible "tin cry".
Tin does not easily oxidize in air but when heated in air readily forms tin oxide.
Tin is obtained mainly from the minerals cassiterite, a tin oxide, and stannite, a tin sulphide. Both may carry some indium: a rare metal with many opto-electronic applications.
Applications of Tin:
- Alloyed Materials: Bronze is an alloy of tin and copper, while the addition of phosphorus creates phosphor bronze. Bell metal is also a copper-tin alloy, containing 22% tin. Tin and lead are alloyed to make pewter (85-99% tin). Babbitt metal for bearings has a high percentage of tin as well. Type metal for printing and fusible metal for fire suppression and electrical safety are other examples of tin alloys.
- Glassmaking: Tin is used in the Pilkington process to produce window glass. In the Pilkington process, molten glass is poured onto a pool of molten tin, effectively creating float glass. The glass floats on the surface of the tin and cools, forming solid glass with flat, parallel surfaces. Most of the window glass produced today is made in this manner.
- Tinplating: Tin bonds readily to iron, and is used for coating lead, zinc and steel to prevent corrosion. Tin-plated steel containers are widely used for food preservation and this forms a large part of the market for metallic tin.
- Solders: Tin has long been used as a solder in the form of an alloy with lead, primarily used for joining pipes or electric circuits. Since the European Union Waste Electrical and Electronic Equipment Directive (WEEED) and Restriction of Hazardous Substances Directive (RoHS) came into effect on 1 July 2006, the use of lead in such alloys has decreased.
- Other Uses: Tin salts can be sprayed onto glass to make electrically conductive coatings used to make panel lighting and frost-free windshields; stannous fluoride is used in some types of toothpaste. Most metal pipes in pipe organs are made of varying amounts of tin/lead alloys. The amount of tin in an organ pipe defines the pipe's tone.