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50. TinName: Tin
Ordinary tin is a silvery-white metal, is malleable, somewhat ductile, and has a highly crystalline structure. Due to the breaking of these crystals, a "tin cry" is heard when a bar is bent. The element has two allotropic forms. On warming, grey, or a-tin, with a cubic structure, changes at 13.2°C into white, or b-tin, the ordinary form of the metal. White tin has a tetragonal structure. When tin is cooled below 13.2°C, it changes slowly from white to grey. This change is affected by impurities such as aluminium and zinc, and can be prevented by small additions of antimony or bismuth. The conversion was first noted as growths on organ pipes in European cathedrals, where it was thought to be the devils work. This conversion was also speculated to be caused microorganisms and was called "tin plague" or "tin disease". Tin resists distilled, sea, and soft tap water, but is attacked by strong acids, alkalis, and acid salts. Oxygen in solution accelerates the attack. When heated in air, tin forms SnO2. It is, or was, used to plate steel, making "tin cans". Tin is used as one component in bell metals. Tin (anglo-Saxon, tin, Latin stannum) is one of the earliest metals known and was used as a component of bronze from antiquity. Because of its hardening effect on copper, tin was used in bronze implements as early as 3,500 BC. Tin mining is believed to have started in Cornwall and Devon ( esp Dartmoor) in Classical times, and a thriving tin trade developed with the civilizations of the Mediterranean. However the pure metal was not used until about 600 BC. The word "tin" has cognates in many Germanic and Celtic languages. The American Heritage Dictionary speculates that the word was borrowed from a pre-Indo-European language. In modern times, the word "tin" is often (improperly) used as a generic phrase for any silvery metal that comes in thin sheets. Most everyday objects that are commonly called tin, such as aluminium foil, beverage cans, and tin cans, are actually made of steel or aluminium, although tin cans do contain a small coating of tin to inhibit rust. Likewise, so-called "tin toys" are usually made of steel, and may or may not have a small coating of tin to inhibit rust. The small amount of tin that is found in canned foods is not harmful to humans. Trialkyl and triaryl tin compounds are biocides and need to be handled with care. Quick links
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