Tin
Definition and meaning of Tin in chemistry.
Tin is a silvery, highly malleable metal identified by the chemical symbol Sn and an atomic number of 50. It is a versatile post-transition metal celebrated for its low melting temperature, impressive corrosion resistance, and profound historical importance in creating durable bronze alloys. The symbol Sn comes from the Latin word stannum, reflecting its ancient extraction and widespread utilization across early civilizations.
In more detail
Located in group 14 of the periodic table, tin is a distinct post-transition metal that visibly exhibits two main allotropes at normal atmospheric pressure: the stable, metallic beta-tin (commonly called white tin) and the nonmetallic, powdery alpha-tin (known as gray tin). The physical phase transition from white tin to gray tin occurs spontaneously at temperatures below 13.2 degrees Celsius, a destructive structural phenomenon historically referred to as tin pest. Tin is heavily extracted on a commercial scale from the primary oxide mineral cassiterite, which contains concentrated tin dioxide (SnO2). It readily forms a wide variety of chemical compounds in both the +2 and +4 oxidation states, with the +4 state generally being much more stable under typical environmental conditions. Because metallic tin is highly resistant to water-induced oxidation and atmospheric corrosion, it effectively protects other more susceptible structural metals when applied as a thin, protective surface coating. Furthermore, molten tin is uniquely employed in modern glassmaking, where liquid glass is floated on a bath of liquid tin to produce perfectly flat window panels.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Sn |
| Atomic number | 50 |
| Atomic mass | 118.71 u |
| Category | Post Transition Metal |
| State at room temperature | Solid |
| Melting point | 231.93 °C |
| Boiling point | 2602 °C |
| Allotropes | White tin and gray tin |
Tin is frequently used to plate the interior surfaces of steel cans, safely preventing the underlying steel from rusting and protecting the preserved food from harmful metal contamination.
Frequently asked questions
What is the phenomenon called tin pest?
Tin pest is the spontaneous physical transformation of metallic white tin into brittle gray tin at cold temperatures, which can destroy the material's overall structural integrity.
Is tin safe for food contact?
Metallic tin is generally non-toxic and entirely safe for human food contact, which explains why it is historically used in tin cans and various cooking utensils.