[CHEM] Tin 的introduct, abundant+uses

Tin is a chemical element in the periodic table that has the symbol Sn and atomic number 50. This silvery, malleable poor metal that is not easily oxidized in air and resists corrosion, is found in many alloys and is used to coat other metals to prevent corrosion. Tin is obtained chiefly from the mineral cassiterite, where it occurs as an oxide.

Tin is produced by reducing the ore with coal in a reverberatory furnace. This metal is a relatively scarce element with an abundance in the Earth's crust of about 2 ppm (parts per million).

Tin bonds readily to iron, and has been used for coating lead or 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.

Other uses include:
1) Important tin alloys are: bronze, bell metal, Babbitt metal, die casting alloy, pewter, phosphor bronze, soft solder, and White metal

2) Tin foil was once a common wrapping material for foods and drugs; replaced in the early 20th century by the use of aluminium foil.