← Periodic table · Post-transition metals
Tin (Sn)
Tin (symbol Sn) is the chemical element with atomic number 50: a post-transition metal, solid at 0 °C, with an atomic mass of 118.71 u. Known since antiquity.
Tin, mixed with copper, gave us bronze, and with it an entire period of human history. Today it is used mainly to solder electronic components and to protect the steel of food cans. It has the peculiar habit of “crying” when bent.
Key facts
- Atomic number
- 50
- Symbol
- Sn
- French name
- Étain
- Atomic mass
- 118.71 u
- Molar mass
- 118.71 g/mol
- Family
- Post-transition metals
- Position
- period 5, group 14, p-block
- State at 0 °C
- Solid
- Melting point
- 231.9 °C
- Boiling point
- 2,601.9 °C
- Density
- 7.29 g/cm³
- Electronegativity (Pauling)
- 1.96
- First ionization energy
- 709 kJ/mol
- Atomic radius
- 145 pm
- Electron configuration
- [Kr] 4d¹⁰ 5s² 5p²
- Abundance in Earth's crust
- 2.3 ppm (51st most abundant element)
- Indicative price
- 19 $/kg (order of magnitude)
- Radioactive
- no
- Discovery
- Antiquity
Origin of the name
An Old English word; the symbol Sn comes from the Latin stannum.
What does tin look like?
A shiny, silvery-white metal, soft and malleable, that melts at just 232 °C. Below 13 °C, it can slowly turn into a gray powder: this is “tin pest.”
Where is tin found?
About 2 ppm of Earth's crust. It is almost entirely mined from a single mineral, cassiterite, found in veins or in alluvial deposits.
Natural sources
- Cassiterite
- Stannite
How is tin produced?
Cassiterite (tin oxide) is concentrated and then reduced with carbon in a furnace. World mine output is about 300,000 tonnes a year.
Top producers
- China
- Indonesia
- Myanmar
- Peru
- Democratic Republic of the Congo
- Brazil
What is tin used for?
- Solder for electronic circuits (nearly half of demand).
- Tinplate: a thin protective coating on the steel of food cans.
- PVC stabilizers and chemicals.
- Bronze, pewter and other alloys.
- The bath of molten tin on which flat glass floats (float process).
In everyday life
- Food can
- Solder joints on a computer motherboard
- Window glass (made on molten tin)
- Pewter and bronze objects
Role in living things
No proven biological role. Metallic tin has low toxicity, but organic tin compounds, such as the tributyltin in antifouling boat paints, were highly toxic to marine life and were banned in 2008.
Hazards of tin
Low toxicity in metallic or mineral form. Some organotin compounds, however, are toxic to the nervous and immune systems.
Cosmic origin
- Dying stars: Made slowly in red giants (stars like the Sun at the end of their lives).
- Neutron stars: Created when two neutron stars collide — the “forge” of gold.
History of tin
Bronze appeared in the Near East around 3000 BC, implying long-distance trade in tin, notably from Cornwall. The symbol Sn comes from the Latin stannum.
Did you know?
- Legend has it that tin pest crumbled the buttons of Napoleon's soldiers in Russia; the story is popular but unsupported.
- The “tin cry” is an audible crackle produced by crystals slipping past each other when a bar is bent.
- Kitchen “tin foil” has actually been made of aluminium for decades.
Isotopes of tin
Ten stable isotopes: the all-time record in the periodic table, thanks to its “magic” number of 50 protons.
- tin-112: 0.97% of natural tin, stable
- tin-113: radioactive, half-life 115 days. Parent in the indium-113m generator.
- tin-114: 0.66% of natural tin, stable
- tin-115: 0.34% of natural tin, stable
- tin-116: 14.54% of natural tin, stable
- tin-117: 7.68% of natural tin, stable
- tin-117m: radioactive, half-life 14 days. Studied for easing bone pain, and used to treat arthritis in dogs.
- tin-118: 24.22% of natural tin, stable
- tin-119: 8.59% of natural tin, stable
- tin-119m: radioactive, half-life 293 days. Source for Mössbauer spectroscopy of tin compounds.
- tin-120: 32.58% of natural tin, stable
- tin-122: 4.63% of natural tin, stable
- tin-124: 5.79% of natural tin, stable
- tin-126: radioactive, half-life 230,000 years. Long-lived fission product in nuclear waste.
Related elements
Same family (post-transition metals): Aluminium (Al), Gallium (Ga), Indium (In), Thallium (Tl), Lead (Pb), Bismuth (Bi), Polonium (Po).
Same column (group 14): Carbon (C), Silicon (Si), Germanium (Ge), Lead (Pb), Flerovium (Fl).