What does Sn stand for?

Sn comes from the Latin word "stannum," the ancient name for tin. The symbol has been used in chemistry since the early systematic naming period and is retained in the modern periodic table.

What are the common oxidation states of tin?

Tin primarily exists as Sn(+2) (stannous) and Sn(+4) (stannic). Sn(+4) is the more stable state under oxidizing conditions, while Sn(+2) is common in ionic compounds such as tin(II) chloride (SnCl2).

Why does tin have so many stable isotopes?

Tin has ten stable isotopes (more than any other element) because atomic number 50 is a "magic number" in nuclear physics — the nucleus has a fully closed shell of protons, making it exceptionally stable against radioactive decay.

What are the allotropes of tin?

Tin has two main allotropes: white tin (beta-Sn), the common metallic form stable above 13.2 C, and gray tin (alpha-Sn), a brittle semiconductor stable below 13.2 C. The conversion from white to gray tin is called "tin pest" and can cause tin objects to crumble in very cold environments.

Inorganic tin compounds are generally considered to have low toxicity; the body absorbs little from food or soil. Organotin compounds, however, can be highly toxic and are regulated in industrial and agricultural contexts.

Tin Element Properties

Name: Tin Element Properties
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Author: Nham Vu

A complete reference card for Tin (Sn, element 50) — atomic data, electron configuration, oxidation states, physical and chemical properties, and common applications.

Atomic Number

Tin

Post-Transition Metal • Group 14 • Period 5

Block: p Series: Post-Transition Metal

Quick Facts

Standard Atomic Weight: 118.710 u
Electronegativity (Pauling): 1.96
Atomic Radius: 145 pm
Covalent Radius: 139 pm
Van der Waals Radius: 217 pm
Oxidation States: -4, +2, +4
Stable Isotopes: 10 (most of any element)
CAS Number: 7440-31-5

Electron Configuration

[Kr] 4d¹⁰ 5s² 5p²

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p²

Shell 1 (K)

Shell 2 (L)

Shell 3 (M)

Shell 4 (N)

Shell 5 (O)

Valence Electrons

4 (5s² 5p²)

Physical Properties

Phase at STP Solid

Appearance Silvery-white

Melting Point 231.93 °C (449.47 °F)

Boiling Point 2602 °C (4716 °F)

Density (white Sn) 7.265 g/cm³

Density (gray Sn) 5.769 g/cm³

Heat of Fusion 7.03 kJ/mol

Heat of Vaporization 296 kJ/mol

Molar Heat Capacity 27.112 J/(mol·K)

Thermal Conductivity 66.8 W/(m·K)

Electrical Resistivity 115 nΩ·m (20 °C)

Mohs Hardness 1.5

Allotropes

White Tin (β-Sn)

Stable above 13.2 °C

Body-centered tetragonal crystal structure
Metallic, malleable, ductile
Electrically conductive
The common commercial form

Gray Tin (α-Sn)

Stable below 13.2 °C

Diamond cubic crystal structure
Brittle, powdery semiconductor
Conversion known as "tin pest"
Caused historical damage to tin organ pipes

Oxidation States

-4

Sn(-4)

Rare, reductive

Found in stannide intermetallic compounds (e.g., Mg₂Sn). Uncommon outside solid-state chemistry.

Sn(+2) — Stannous

Common, reducing agent

Found in SnCl₂ (tin(II) chloride), SnO, SnSO₄. Acts as a reducing agent; easily oxidized to Sn(+4).

Sn(+4) — Stannic

Most stable, oxidizing

Found in SnO₂ (cassiterite), SnCl₄, organotin compounds. The most stable oxidation state under aerobic conditions.

Stable Isotopes (10 stable isotopes — more than any other element)

Isotope	Mass Number	Atomic Mass (u)	Natural Abundance	Neutrons
¹¹²Sn	112	111.904822	0.97%	62
¹¹⁴Sn	114	113.902783	0.66%	64
¹¹⁵Sn	115	114.903347	0.34%	65
¹¹⁶Sn	116	115.901745	14.54%	66
¹¹⁷Sn	117	116.902954	7.68%	67
¹¹⁸Sn	118	117.901607	24.22%	68
¹¹⁹Sn	119	118.903311	8.59%	69
¹²⁰Sn	120	119.902202	32.58%	70
¹²²Sn	122	121.903440	4.63%	72
¹²⁴Sn	124	123.905277	5.79%	74

Chemical Properties

Resists corrosion from water and dilute acids due to a protective oxide layer (SnO₂).
Dissolves in concentrated HCl and H₂SO₄; reacts with concentrated HNO₃ to form hydrated tin(IV) oxide.
Amphoteric metal: reacts with both strong acids and strong bases (e.g., NaOH to form stannate ions).
Forms alloys readily with copper (bronze), lead (solder), antimony, and bismuth.
Sn(+2) acts as a reducing agent; commonly used in redox titrations and electroplating baths.
Emits a characteristic "tin cry" (crackling sound) when bent due to crystal twinning.

Industrial Applications

Tinplate: thin steel sheets coated with tin for food cans, packaging, and corrosion protection.
Solder: Sn-Ag-Cu (SAC) lead-free solder alloys dominate modern electronics assembly.
Bronze: Cu-Sn alloy used in bearings, bells, sculptures, and marine hardware.
Indium tin oxide (ITO): transparent conductor used in touchscreens, LCD displays, and solar cells.
Organotin chemicals: used as PVC stabilizers, antifouling agents (now largely banned), and catalysts.
Li-ion battery anodes: tin and tin-alloy anodes offer higher capacity than graphite in next-generation batteries.

History & Discovery

Known Since Antiquity

Tin has been used since at least 3500 BCE. Bronze Age civilizations deliberately alloyed tin with copper to produce bronze, transforming tools and weapons.

Name Origin

The English name "tin" has Germanic roots. The symbol Sn derives from the Latin "stannum," which originally referred to a lead-silver alloy before settling on tin.

Primary Ore

Cassiterite (SnO₂) is the overwhelmingly dominant commercial ore, mined mainly in China, Indonesia, Myanmar, and Peru. It contains up to 78.8% tin by mass.

Summary