Tin

Tin is a chemical element with the symbol Sn and atomic number 50. It is a soft, malleable metal with a silvery appearance that slowly tarnishes when exposed to air, forming a protective oxide layer. Tin is relatively resistant to corrosion in many environments, which makes it useful as a coating or in alloys.

The most important commercial tin ore is cassiterite, which is tin oxide (SnO2). Tin occurs in the Earth's crust at low concentrations and is mined in several countries, including China, Indonesia, Peru, and Bolivia. After mining, the ore is concentrated and reduced with carbon to produce metallic tin, which is refined into ingots and ingots used for alloying and further processing.

Key physical and chemical properties include a melting point of about 231.93°C and a boiling point around 2,625°C. Its density is approximately 7.31 g/cm3 at room temperature. Tin is a post-transition metal that is relatively soft and ductile. It commonly exhibits oxidation states of +2 and +4. At low temperatures, tin can transform from white tin (beta form) to gray tin (alpha form), a phase change known as tin pest that can make the metal brittle.

Industrial uses of tin are diverse. It is widely used as a corrosion-resistant coating for steel (tinplate) and in food containers. Tin is a principal component of bronze (an alloy with copper) and is a major constituent of pewter. Tin is also employed in solder, often in lead-free formulations such as tin-silver-copper alloys, as well as in coatings for glass and ceramics and in certain catalytic and semiconductor applications, including tin oxide (SnO2) used in sensors and catalysts. Safety considerations focus on inorganic tin compounds and especially organotin compounds, which can be toxic.