50 Sn 118.71

Tin

Post-transition metal Stannum solid

[Kr] 4d¹⁰ 5s² 5p² · 2 · 8 · 18 · 18 · 4

← In Indium Sb Antimony →

The metal whose alloy with copper opened the Bronze Age. Tin has ten stable isotopes, more than any other element, a consequence of the magic proton number 50.

3D model

Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.

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Atomic properties

Atomic number: 50
Atomic mass: 118.71 а.е.м.
Electron configuration: [Kr] 4d¹⁰ 5s² 5p²
Electrons per shell: 2 · 8 · 18 · 18 · 4
Block: p-block
Group: Carbon group
Period: 5
Electronegativity (Pauling): 1.96
Electronegativity (Allen): 1.82
Atomic radius: 145 pm
Covalent radius: 139 pm
Van der Waals radius: 217 pm
Ionisation energy 1: 708.6 kJ/mol
Ionisation energy 2: 1 411.8 kJ/mol
Ionisation energy 3: 2 943 kJ/mol
Ionisation energy 4: 3 930.3 kJ/mol
Ionisation energy 5: 7 456 kJ/mol
Electron affinity: 107.3 kJ/mol
Common oxidation states: +2, +4
Oxidation states: -4, -3, -2, -1, +1, +2, +3, +4

Physical properties

State at 25 °C: solid
Density: 7.265 g/cm³
Melting point: 505.08 K · 231.9 °C
Boiling point: 2 875 K · 2 601.9 °C
Speed of sound: 2 500 m/s

Thermal properties

Heat of fusion: 7.03 kJ/mol
Heat of vaporisation: 296.1 kJ/mol
Specific heat capacity: 0.228 J/(g·K)
Thermal conductivity: 66.8 W/(m·K)

Mechanical properties

Young's modulus: 50 GPa
Shear modulus: 18 GPa
Bulk modulus: 58 GPa
Poisson ratio: 0.36
Mohs hardness: 1.5
Brinell hardness: 51 MPa

Electrical and magnetic properties

Electrical resistivity: 115 nΩ·m
Magnetic ordering: diamagnetic
Curie point: no data
Néel point: no data
Superconducting point: 3.72 K

Crystal structure

Crystal structure: tetragonal
Lattice constants: a = 583.18 pm · c = 318.19 pm

Abundance

In the crust: 2.3 mg/kg
In the ocean: 8·10⁻⁷ mg/L
In the universe: 0.004 mg/kg
In the human body: 0.2 mg/kg

Isotopes

Isotope	Abundance	Half-life	Decay mode
¹¹²Sn	0.97 %	stable	—
¹¹⁴Sn	0.66 %	stable	—
¹¹⁵Sn	0.34 %	stable	—
¹¹⁶Sn	14.54 %	stable	—
¹¹⁷Sn	7.68 %	stable	—
¹¹⁸Sn	24.22 %	stable	—
¹¹⁹Sn	8.59 %	stable	—
¹²⁰Sn	32.58 %	stable	—
¹²²Sn	4.63 %	stable	—
¹²⁴Sn	5.79 %	stable	—

Ten stable isotopes, the outright record for the table. The reason is that 50 protons close a nuclear shell, which makes the nucleus exceptionally stable.

Discovery

Year of discovery: known since antiquity
Discovered by: known since antiquity
Where: no data
Origin of the name: from Latin stannum; alloyed with copper it made the Bronze Age

History

Tin was smelted from the fourth millennium BCE. Cornish tin mines supplied the Mediterranean long before Rome; the Phoenicians called those lands the Tin Islands.

Where it occurs

2.3 mg/kg of the crust. Cassiterite, SnO₂, is essentially the only ore. The largest producers are China, Indonesia and Myanmar.

How it is produced

Carbon reduction of cassiterite in reverberatory furnaces, followed by refining. A substantial share is recycled from solder and tinplate.

Role in living things

Not considered essential. Inorganic tin compounds are of low toxicity; organotin compounds are decidedly not.

Safety

Tributyltin, once used in ship antifouling paint, proved a powerful endocrine disruptor and was banned by international convention in 2008.

Uses

Solders — the largest use, especially since lead was banned from electronics
Tinplate: a thin tin layer protects the steel of a food can
Bronze and pewter
The float process for sheet glass: molten glass is poured onto a bath of liquid tin
PVC stabilisers and catalysts

Curiosities

Tin has more stable isotopes than any other element.
Tin pest: below 13 °C white tin slowly turns into a grey powder, destroying the object.
Tin pest is one proposed explanation for the failure of Scott's expedition — fuel leaked from tin-soldered cans.
Bent tin gives a characteristic crackle, the tin cry, as its crystals rearrange.