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Glossary
Tin (Sn)
Tin is a soft, silvery-white metal with the chemical symbol Sn (from the Latin stannum) and atomic number 50. It belongs to the post-transition metals group in the periodic table and is known for its malleability, corrosion resistance, and low melting point (231.9°C or 449.4°F). Tin has been used by humans for thousands of years, most notably as one of the key ingredients in bronze—an alloy of copper and tin that marked a major technological advance in ancient civilization.
In its pure form, tin is relatively weak and soft, which makes it easy to bend, roll, or shape. It has a bright metallic luster and produces a distinctive “tin cry” sound when bent, caused by the movement of its crystal structure. One of its most notable characteristics is its resistance to corrosion. When exposed to air, tin forms a thin, stable oxide layer that protects the underlying metal from further oxidation—this property makes it ideal for coating other metals such as steel or copper.
The most common modern use of tin is in tin plating, where it serves as a protective coating for steel cans and containers, preventing rust and oxidation—this is why we call them “tin cans,” even though the bulk of the can is actually steel. Tin is also used in soldering, where alloys of tin and lead (or tin and silver in lead-free versions) join electrical and plumbing components.
Another major application is in bronze (Cu + Sn), pewter (Sn + Sb + Cu), and bearing metals where tin improves wear resistance and lubrication. In electronics, tin oxide and indium tin oxide (ITO) are used in transparent conductive coatings for touchscreens, solar panels, and displays.
Tin can exist in two main allotropes:
- White tin (β-tin): The metallic, stable form at room temperature.
- Gray tin (α-tin): A brittle, nonmetallic form that appears below 13.2°C (55.8°F). The transition from white to gray tin is known as “tin pest”, which can cause old tin objects to crumble in cold conditions.
Tin is primarily extracted from the mineral cassiterite (SnO₂), found in regions such as China, Indonesia, Peru, Bolivia, and the Democratic Republic of Congo.
