Chemical formula: Sn
Atomic number: 50
Series: Metal
Appearance: Shiny silver
Mass fraction of earth shell: 35 ppm
Physical state: Solid
Density: 5.77 g-cm3
Melting point: 231.93°C
Boiling point: 2620°C
Mohs hardness: 1.5
Molar volume: 16.29-10?6 m3 / mol
Heat of melting: 7.03 kJ / mol
Heat of evaporation: 290 kJ / mol
Physical and chemical properties
Tin is a relatively soft, silvery, lustrous heavy metal. It has a low Mohs
hardness of only 1.5, so it can be easily scratched with a knife. However, tin
is not as soft as lead or indium. When a rod made of pure tin is bent, the crack
popping sound is also commonly referred to as a "pe call". Pure tin has a
relatively low melting point (231.93°C), which is why it can be melted by
candlelight or a lighter.
The use of
Today, about half of the tin traded worldwide is used for tin plating in the
manufacture of cans or car bodies. Another big item is the classic tin solder.
The material melts at about 180 degrees Celsius and typically contains about 62
percent tin, 36 percent lead and 2 percent copper. The addition of bismuth
lowers the melting temperature. Lead-free alternatives rely on the addition of 2
to 5 percent silver. Tin is also used in a number of different ways to produce
low melting point alloys with up to 60% tin content.
Another area of application is machine components, such as bearings in machine
shafts. Here, tin ensures better sliding properties.
Toxicology and hazards
Tin and its inorganic compounds are far less toxic than lead, but not completely
free of problems. The element enters the body mainly through the ingestion of
tin-containing foods. For example, acute symptoms of poisoning have been
observed in people who drank lime juice from a tin can. Inorganic tin compounds
are converted to organotin compounds in small amounts in the gastrointestinal
tract. They are more toxic than inorganic tin compounds. In 1954, about 100
people died in France from cerebral edema after taking the drug.
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