Tin (50)

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 α-tin, alpha) tin (with a cubic structure), changes at 13.2°C into white (β-tin, beta), which is 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 aluminum 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 (wasn't everything back then?). 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.

•Name: Tin
•Symbol: Sn
•Atomic number: 50
•Atomic weight: 118.710 (7) [see note g]
•Standard state: solid at 298 K
•CAS Registry ID: 7440-31-5
•Group in periodic table: 14
•Group name: (none)
•Period in periodic table: 5
•Block in periodic table: p-block
•Color: silvery lustrous grey
•Classification: Metallic

Historical information
Origin of name: from the Anglo-Saxon word "tin" (the origin of the symbol Sn comes from the Latin word "stannum" meaning "tin"). Tin was known to the ancients and is mentioned in the Old Testament. Early metal workers found it too soft for most purposes but mixed with copper it gives the alloy bronze, of Bronze Age fame.

Tin is one of the elements which has an alchemical symbol, which looks almost like a trident.

Physical properties
•Melting point: 505.08 [or 231.93 °C (449.47 °F)] K
•Boiling point: 2875 [or 2602 °C (4716 °F)] K
•Density of solid: 7310 kg m-3

Orbital properties
•Ground state electron configuration: [Kr].4d10.5s2.5p2
•Shell structure: 2.8.18.18.4
•Term symbol: 3P0

Isolation
There is normally little need to isolate tin metal in the laboratory as it is readily available commercially. Tin is commonly available as the mineral cassiterite, SnO2. Reduction of this dioxide with burning coal results in tin metal and was probably how tin was made by the ancients.

SnO2 + 2C → Sn + 2CO