Tin
Atomic Data
| Atomic Number | 50 |
| Symbol | Sn |
| Atomic Weight | 118.71 u |
| Density (STP) | 7.287 g/cm³ |
| Melting Point | 231.93 °C (505.08 K) |
| Boiling Point | 2601.85 °C (2875 K) |
| Electronegativity | 1.96 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p2 |
| Oxidation States | +2, +4 |
| Phase at STP | Solid |
| Category | Post-Transition Metal |
| Period / Group | 5 / 14 |
| CAS Number | 7440-31-5 |
Electron Configuration
[Kr] 4d10 5s2 5p2
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 10 | 28 |
| N | 4 | 4s | 2 | 30 |
| N | 4 | 4p | 6 | 36 |
| N | 4 | 4d | 10 | 46 |
| O | 5 | 5s | 2 | 48 |
| O | 5 | 5p | 2 | 50 |
| Total | 50 | 50 | ||
Isotopes of Tin
Tin has ten naturally occurring stable isotopes. The most abundant is ¹²⁰Sn, comprising 32.58% of all naturally occurring Tin.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Tin-112 | ¹¹²Sn | 50 | 62 | 0.97 | Stable |
| Tin-114 | ¹¹⁴Sn | 50 | 64 | 0.66 | Stable |
| Tin-115 | ¹¹⁵Sn | 50 | 65 | 0.34 | Stable |
| Tin-116 | ¹¹⁶Sn | 50 | 66 | 14.54 | Stable |
| Tin-117 | ¹¹⁷Sn | 50 | 67 | 7.68 | Stable |
| Tin-118 | ¹¹⁸Sn | 50 | 68 | 24.22 | Stable |
| Tin-119 | ¹¹⁹Sn | 50 | 69 | 8.59 | Stable |
| Tin-120 | ¹²⁰Sn | 50 | 70 | 32.58 | Stable |
| Tin-122 | ¹²²Sn | 50 | 72 | 4.63 | Stable |
| Tin-124 | ¹²⁴Sn | 50 | 74 | 5.79 | Stable |
Abundance & Occurrence
Tin is present in Earth's crust at approximately 2.3 ppm by mass and at approximately 4 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Universe (ppm by mass)
Discovery & History
Read more about the discovery of the periodic table of elements →
Safety & Handling
- Organotin compounds: highly toxic: Organotins such as tributyltin (TBT) and trimethyltin are acutely neurotoxic and endocrine-disrupting; TBT in antifouling marine paint caused widespread ecological damage and is now globally restricted.
- Tin oxide dust: SnO2 dust causes stannosis, a benign pneumoconiosis that is radiologically visible but does not cause significant lung function impairment at normal exposure levels.
- Tin pest: Below 13.2 °C, tin metal undergoes allotropic transformation to grey tin ('tin pest'), crumbling to powder; this is historically significant but not a safety hazard under normal conditions.
- Soldering fumes: Soldering with tin-lead or tin-silver alloys generates flux fumes; rosin flux fumes are respiratory sensitisers and can cause occupational asthma: ensure extraction ventilation at all soldering stations.
Tin in the Real World
Real-World Uses
- Food can linings (tinplate): Electrolytically tinned steel sheet (tinplate) is the substrate for food and beverage cans; the thin tin coating prevents corrosion of the steel and avoids any taste contamination of canned food.
- Solder alloys: Tin-silver-copper (SAC) and other tin-based lead-free solders are used throughout the electronics industry to form reliable electrical and mechanical joints on printed circuit boards following the RoHS restriction on lead.
- Bronze and pewter: Tin alloyed with copper produces bronze (used in bearings, bells, sculptures, and historical artefacts), while tin-antimony-copper pewter alloys are used for tableware, decorative figurines, and ecclesiastical items.
- Flat glass manufacture: The float glass process, which produces all modern flat glass for windows and mirrors, involves floating molten glass on a bath of molten tin to produce a perfectly flat, polished surface.
- Organotin stabilisers: Dibutyltin and dioctyltin compounds are heat and UV stabilisers in PVC pipes and window profiles; they prevent thermal degradation of PVC during processing and long-term outdoor service.
Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.
Frequently Asked Questions
What is tin used for?
Tin is best known historically as a component of bronze (tin-copper alloy) and pewter. Today its main uses are in solder (tin-lead or lead-free tin alloys used in electronics), tin plating of steel (for food cans: 'tin cans' are steel cans with a thin tin coating), and in organotin compounds used as PVC stabilisers and biocides. Tin is also used in window glass production (the float glass process uses a bath of molten tin).
What is tin pest?
Tin pest is a phase transformation in which white tin (beta-tin, the familiar shiny metal) converts to grey tin (alpha-tin, a powdery crumbling form) at temperatures below 13.2 °C. The transformation is autocatalytic: grey tin spreads from nucleation sites like a disease. Napoleon's army's retreat from Russia in 1812 may have been partly worsened by tin pest causing soldiers' tin coat buttons to crumble in the extreme cold.
How was tin discovered?
Tin is one of the oldest metals known to humanity. Tin artefacts date to around 3500 BCE, and bronze (tin-copper alloy) was so important it defined a prehistoric age. Tin was obtained primarily from cassiterite (SnO2) mined in Cornwall (Britain), Iberia, and later Southeast Asia. The chemical symbol Sn comes from the Latin 'stannum'.
What are lead-free solders and why do they use tin?
Lead-free solders, mandated in most consumer electronics by the EU RoHS directive from 2006, are primarily alloys of tin with silver, copper, bismuth, or other metals. Tin is the base because it has the right melting range for electronics assembly, good wettability on copper, and is not toxic like lead. The most common lead-free solder, SAC305 (96.5% Sn, 3% Ag, 0.5% Cu), has a melting point of about 217–220 °C.