Tin

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indiumtinantimony
Ge

Sn

Pb
Appearance
silvery (left, beta) or gray (right, alpha)
General properties
Name, symbol, number tin, Sn, 50
Pronunciation /ˈtɪn/
Element category post-transition metal
Group, period, block 145, p
Standard atomic weight 118.710 g·mol−1
Electron configuration [Kr] 4d10 5s2 5p2
Electrons per shell 2, 8, 18, 18, 4 (Image)
Physical properties
Phase solid
Density (near r.t.) (white) 7.365 g·cm−3
Density (near r.t.) (gray) 5.769 g·cm−3
Liquid density at m.p. 6.99 g·cm−3
Melting point 505.08 K, 231.93 °C, 449.47 °F
Boiling point 2875 K, 2602 °C, 4716 °F
Heat of fusion (white) 7.03 kJ·mol−1
Heat of vaporization (white) 296.1 kJ·mol−1
Specific heat capacity (25 °C) (white) 27.112 J·mol−1·K−1
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, 2, -4 (amphoteric oxide)
Electronegativity 1.96 (Pauling scale)
Ionization energies 1st: 708.6 kJ·mol−1
2nd: 1411.8 kJ·mol−1
3rd: 2943.0 kJ·mol−1
Atomic radius 140 pm
Covalent radius 139±4 pm
Van der Waals radius 217 pm
Miscellanea
Crystal structure tetragonal
Crystal structure note white
Magnetic ordering (gray) diamagnetic[1], (white) paramagnetic
Electrical resistivity (0 °C) 115 nΩ·m
Thermal conductivity (300 K) 66.8 W·m−1·K−1
Thermal expansion (25 °C) 22.0 µm·m−1·K−1
Speed of sound (thin rod) (r.t.) (rolled)
2730 m·s−1
Young's modulus 50 GPa
Shear modulus 18 GPa
Bulk modulus 58 GPa
Poisson ratio 0.36
Mohs hardness 1.5
Brinell hardness ~350 MPa
CAS registry number 7440-31-5
Most stable isotopes
Main article: Isotopes of tin
iso NA half-life DM DE (MeV) DP
112Sn 0.97% 112Sn is stable with 62 neutrons
114Sn 0.66% 114Sn is stable with 64 neutrons
115Sn 0.34% 115Sn is stable with 65 neutrons
116Sn 14.54% 116Sn is stable with 66 neutrons
117Sn 7.68% 117Sn is stable with 67 neutrons
118Sn 24.22% 118Sn is stable with 68 neutrons
119Sn 8.59% 119Sn is stable with 69 neutrons
120Sn 32.58% 120Sn is stable with 70 neutrons
122Sn 4.63% 122Sn is stable with 72 neutrons
124Sn 5.79% >1×1017 y ββ 2.2870 124Te
126Sn trace 2.3×105 y β 0.380 126Sb
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 is not radioactive.

Properties[change | edit source]

Physical properties[change | edit source]

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[change | edit source]

Salt water and fresh water do not affect tin.

It does dissolve in strong acid to make tin salt.

It does react with some strong bases.

Tin is corrosion (the breakdown of materials due to reactions within its area) resistant to many things.

Chemical compounds[change | edit source]

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.

+4 compounds

+4 compounds are unreactive. Some are colorless.

Occurrence[change | edit source]

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[change | edit source]

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

History[change | edit source]

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[change | edit source]

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[change | edit source]

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

Sources[change | edit source]

  1. Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.