Tin

Tin is a chemical element with symbol Sn (for Latin: stannum) and atomic number 50. It is in Group 14 on the periodic table. It has ten isotopes that are not radioactive, which is more than any other element.

Tin, ₀₀Sn

Tin
Allotropes	silvery-white, β (beta); gray, α (alpha)
Appearance	silvery-white (beta, β) or gray (alpha, α)
Standard atomic weight Ar°(Sn)
	118.710(7)
Tin in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Ge ↑ Sn ↓ Pb indium ← tin → antimony
Group	group 14 (carbon group)
Period	period 5
Block	p-block
Electron configuration	[Kr] 4d10 5s2 5p2
Electrons per shell	2, 8, 18, 18, 4
Physical properties
Phase at STP	solid
Melting point	505.08 K ​(231.93 °C, ​449.47 °F)
Boiling point	2875 K ​(2602 °C, ​4716 °F)
Density (near r.t.)	white, β: 7.265 g/cm3 gray, α: 5.769 g/cm3
when liquid (at m.p.)	6.99 g/cm3
Heat of fusion	white, β: 7.03 kJ/mol
Heat of vaporization	white, β: 296.1 kJ/mol
Molar heat capacity	white, β: 27.112 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1497 1657 1855 2107 2438 2893
Atomic properties
Oxidation states	−4, −3, −2, −1, 0, +1, +2, +3, +4 (an amphoteric oxide)
Electronegativity	Pauling scale: 1.96
Ionization energies	1st: 708.6 kJ/mol 2nd: 1411.8 kJ/mol 3rd: 2943.0 kJ/mol
Atomic radius	empirical: 140 pm
Covalent radius	139±4 pm
Van der Waals radius	217 pm
Spectral lines of tin
Other properties
Natural occurrence	primordial
Crystal structure	​tetragonal white (β)
Crystal structure	​face-centered diamond-cubic gray (α)
Speed of sound thin rod	2730 m/s (at r.t.) (rolled)
Thermal expansion	22.0 µm/(m⋅K) (at 25 °C)
Thermal conductivity	66.8 W/(m⋅K)
Electrical resistivity	115 nΩ⋅m (at 0 °C)
Magnetic ordering	gray: diamagnetic white (β): paramagnetic
Molar magnetic susceptibility	(white) +3.1·10−6 cm3/mol (298 K)
Young's modulus	50 GPa
Shear modulus	18 GPa
Bulk modulus	58 GPa
Poisson ratio	0.36
Brinell hardness	50–440 MPa
CAS Number	7440-31-5
History
Discovery	around 3500 BC
Symbol	"Sn": from Latin stannum
Isotopes of tin
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 112Sn 0.970% stable 114Sn 0.66% stable 115Sn 0.34% stable 116Sn 14.5% stable 117Sn 7.68% stable 118Sn 24.2% stable 119Sn 8.59% stable 120Sn 32.6% stable 122Sn 4.63% stable 124Sn 5.79% stable 126Sn trace 2.3×105 y β− 126Sb

Tin

Properties

Physical properties

Alpha(α) and beta(β) forms of tin

Tin is a silver, somewhat soft metal. It is a post-transition metal. Its melting point is 231.93°C and its boiling point is 2602 °C. It can melt easily in a flame. It is malleable. It makes a crackling sound called tin cry when a piece of it is bent. Tin has more non-radioactive isotopes than any other element.

Tin is found in two allotropes: alpha-tin and beta-tin. Alpha-tin is a brittle, dull, powdery, semimetallic form of tin. It is made when very pure tin is cooled. Beta-tin is the normal shiny, soft, conductive, metallic form. It is made at higher temperatures. The decay of tin by turning from beta-tin to alpha-tin is called tin pest. Alpha-tin is not wanted in many places. When small amounts of other elements like antimony are added, the tin cannot change into alpha-tin. When alpha-tin is heated, it changes into beta-tin.

Tin can be hardened by adding antimony or copper, as well as some other elements. These also make it resistant to tin pest. Tin can also be made very shiny. Tin can make an alloy with copper called bronze.

Chemical properties

Tin resists many corrosive substances and is often used to protect other metals. Salt water and fresh water do not affect tin. It dissolves in strong acids to make tin salts. It reacts with some strong bases.

Chemical compounds

See also: Category:Tin compounds.

Tin forms chemical compounds in two oxidation states: +2 and +4. +2 compounds are reducing agents. Some of them are colorless while others are colored. +4 compounds are more unreactive and act more covalent.

Tin burns in air to make tin(IV) oxide, which is white. Tin(IV) oxide dissolves in acids to make other tin(IV) compounds. Tin(IV) chloride is a colorless fuming liquid when anhydrous and a white solid when hydrated. It easily reacts with water to make tin(IV) oxide and an acid again.

Tin reacts with hydrohalic acids to make tin(II) halides. For example, tin(II) chloride is made when tin dissolves in hydrochloric acid. Tin(IV) halides are made when tin reacts with the halogens. Tin(IV) chloride is made when tin reacts with chlorine. Tin(II) sulfate is different as it does not oxidize to tin(IV) sulfate. Tin(II) oxide is a blue-black solid that burns in air to make tin(IV) oxide.

+2 compounds

+2 compounds are reducing agents. They are about as common as +4 compounds. Some are colorless, while others are colored.

• Tin(II) bromide, yellowish solid
• Tin(II) chloride, white solid
• Tin(II) fluoride, white solid
• Tin(II) iodide, orange solid
• Tin(II) oxide, blue-black solid
• Tin(II) sulfate, white solid
• Tin(II) sulfide, dark brown solid

+4 compounds

+4 compounds are unreactive. Some are colorless.

• Tin(IV) bromide, colorless solid
• Tin(IV) chloride, colorless liquid or solid
• Tin(IV) fluoride, colorless solid
• Tin(IV) iodide, orange solid
• Tin(IV) oxide, colorless solid
• Tin(IV) sulfide, gold-colored solid

• 
  Tin(II) chloride
• 
  Hydrated tin(IV) chloride
• 
  Anhydrous tin(IV) chloride
• 
  Tin(IV) iodide
• 
  Tin(IV) oxide
• 
  Tin(II) oxide

Occurrence

Cassiterite

Tin is not found as a metal in the ground. It is normally in the form of cassiterite. Cassiterite is a mineral containg tin(IV) oxide. The cassiterite is normally found downstream of the cassiterite deposit when it is by a stream or river. Tin is also found in some complicated sulfide minerals.

Tin does not have any major job in the human body.

Preparation

Tin is made by heating cassiterite with carbon in a furnace. China is the biggest maker of tin.

History

People discovered tin long ago and used it with other metals. When copper and tin are mixed together, bronze is made. Bronze was important in the past, because it was one of the strongest metals available, which meant it was useful in weapons and tools. Bronze changed the world when it was first invented, starting the Bronze Age. People organized themselves more, because making tools from bronze was harder than making them from rock and wood like they did before.

Uses

Pewter plate

Tin solder without lead

Tin is used in solder. Solder used to contain a mixture of lead and tin. Now the lead is removed because of its toxicity.

Tin is also used to make pewter, which is mainly tin mixed with a small amount of copper and other metals. Babbitt metal also has tin in it. Tin is used to coat several metals, like lead and steel. Tin plated steel containers are used to store foods. The pipes on a pipe organ are made of tin. Tin foil was used before aluminium foil. Tin was one of the first superconductors to be found. Organotin compounds are more common than almost any other organometal compound. They are used in some PVC pipes to stop them from decaying. Organotin compounds are toxic, though.

Safety

Tin is not toxic, but tin compounds are very toxic to marine life. They are a little toxic to humans.