Tin

indium – tin – antimony Ge Sn Pb       Full table
General
Name, Symbol, Number	tin, Sn, 50
Chemical series	poor metals
Group, Period, Block	14 (IVA), 5, p
Density, Hardness	7310 kg/m3, 1.5
Appearance	silvery lustrous gray
Atomic properties
Atomic weight	118.710 amu
Atomic radius (calc.)	145 (145) pm
Covalent radius	141 pm
van der Waals radius	217 pm
Electron configuration	[Kr]4d10 5s2 5p2
e- 's per energy level	2, 8, 18, 18, 4
Oxidation states (Oxide)	4,2 (amphoteric)
Crystal structure	Tetragonal
Physical properties
State of matter	Solid
Melting point	505.08 K (231.93 ?C)
Boiling point	2875 K (2602.22 ?C)
Molar volume	16.29 ×10-6 m3/mol
Heat of vaporization	295.8 kJ/mol
Heat of fusion	7.029 kJ/mol
Vapor pressure	5.78 E-21 Pa at 505 K
Speed of sound	2500 m/s at 293.15 K
Miscellaneous
Electronegativity	1.96 (Pauling scale)
Specific heat capacity	228 J/(kg*K)
Electrical conductivity	9.17 106/(m·ohm)
Thermal conductivity	66.6 W/(m*K)
1st ionization potential	708.6 kJ/mol
2nd ionization potential	1411.8 kJ/mol
3rd ionization potential	2943.0 kJ/mol
4th ionization potential	3930.3 kJ/mol
5th ionization potential	7456 kJ/mol
Most stable isotopes
iso NA half-life DM DE MeV DP 112Sn 0.97% Sn is stable with 62 neutrons 114Sn 0.65% Sn is stable with 64 neutrons 115Sn 0.34% Sn is stable with 65 neutrons 116Sn 14.54% Sn is stable with 66 neutrons 117Sn 7.68% Sn is stable with 67 neutrons 118Sn 24.23% Sn is stable with 68 neutrons 119Sn 8.59% Sn is stable with 69 neutrons 120Sn 32.59% Sn is stable with 70 neutrons meta state 0.006 MeV 55 y IT Beta- 0.006 0.394 121Sb 122Sn 4.63% Sn is stable with 72 neutrons 124Sn 5.79% Sn is stable with 74 neutrons 126Sn {syn.} ~1 E5 y Beta- 0.380 126Sb
SI units & STP are used except where noted.

Tin is a chemical element in the periodic table that has the symbol Sn (L. Stannum) and atomic number 50. This silvery, malleable poor metal that is not easily oxidized in air and resists corrosion is found in many alloys and is used to coat other metals to prevent corrosion. Tin is obtained chiefly from the mineral cassiterite where it occurs as an oxide.

Contents

1 Notable characteristics 2 Allotropes 3 Applications 4 History 5 Occurrence 6 Isotopes 7 Precautions 8 References

Notable characteristics

Tin is a malleable, ductile, highly crystalline, silvery-white metal whose crystal structure causes a "tin cry" when a bar of tin is bent (caused by crystals breaking). This metal resists corrosion from distilled sea and soft tap water, but can be attacked by strong acids, alkalis, and by acid salts. Tin acts as a catalyst when oxygen is in solution and helps accelerate chemical attack.

Tin forms Sn₂ when it is heated in the presence of air. Sn₂, in turn, is feebly acidic and forms stannate (tin) salts with basic oxides. Tin can be highly polished and is used as a protective coat for other metals in order to prevent corrosion or other chemical action. This metal combines directly with chlorine and oxygen and displaces hydrogen from dilute acids. Tin is malleable at ordinary temperatures but is brittle when it is heated.

Allotropes

Solid tin has two allotropes at normal pressure. At low temperatures it exists as gray or alpha tin, which has a cubic crystal structure similar to silicon and germanium. When warmed above that 13.2 ?C it changes into white or beta tin, which is metallic and has a tetragonal structure. It slowly changes back to the gray form when cooled, which is called the tin pest or tin disease. However, this transformation is affected by impurities such as aluminium and zinc and can be prevented from occurring through the addition of antimony or bismuth.

Applications

Tin bonds readily to iron, and has been used for coating lead or zinc and steel to prevent corrosion. Tin-plated steel containers are widely used for food preservation, and this forms a large part of the market for metallic tin. British English calls them "tins"; Americans call them "cans". One thus-derived use of the slang term "tinnie" or "tinny" means "can of beer".

Other uses:

• Some important tin alloys are: bronze, bell metal, Babbitt metal, die casting alloy, pewter, phosphor bronze, soft solder, and White metal.
• The most important salt formed is tin chloride, which has found use as a reducing agent and as a mordant in the calico printing process. Electrically conductive coatings are produced when tin salts are sprayed onto glass. These coatings have been used in panel lighting and in the production of frost-free windshields.
• Window glass is most often made via floating molten glass on top of molten tin (creating float glass) in order to make a flat surface (this is called the "Pilkington process").
• Tin is also used in solders for joining pipes or electrical/electronic circuits, in bearing alloys, in glass-making, and in a wide range of tin chemical applications. Although of higher melting point that a lead-tin alloy the use of pure tin or tin alloyed with other metals in these applications is rapidly supplanting the use of the previously common lead–containing alloys in order to eliminate the problems of toxicity caused by lead.
• Tin foil was once a common wrapping material for foods and drugs; now replaced by the use of aluminum foil, which is commonly referred to as tin foil. Hence one use of the slang term "tinnie" or "tinny" for a small retail package of a drug such as cannabis or for a can of beer.

Tin becomes a superconductor below 3.72 K. In fact, tin was one of the first superconductors to be studied; the Meissner effect, one of the characteristic features of superconductors, was first discovered in superconducting tin crystals. The niobium-tin compound Nb₃Sn is commercially used as wires for superconducting magnets, due to the material's high critical temperature (18K) and critical magnetic field (25 T). A superconducting magnet weighing only a couple of kilograms is capable of producing magnetic fields comparable to a conventional electromagnet weighing tons.

History

Tin (anglo-Saxon, tin, Latin stannum) is one of the earliest metals known and was used as a component of bronze from antiquity. Because of its hardening effect on copper, tin was used in bronze implements as early as 3,500 BC. Tin mining is believed to have started in Cornwall and Devon ( esp Dartmoor) in Classical times, and a thriving tin trade developed with the civilizations of the Mediterranean. However the pure metal was not used until about 600 BC.

The word "tin" has cognates in many Germanic and Celtic languages. The American Heritage Dictionary speculates that the word was borrowed from a pre-Indo-European language.

The alchemical symbol for tin is shown on the right.

In modern times, the word "tin" is often (improperly) used as a generic phrase for any silvery metal that comes in thin sheets. Most everyday objects that are commonly called tin, such as aluminium foil, beverage cans, and tin cans, are actually made of steel or aluminium, although tin cans do contain a small coating of tin to inhibit rust. Likewise, so-called "tin toys" are usually made of steel, and may or may not have a small coating of tin to inhibit rust.

Occurrence

About 35 countries mine tin throughout the world. Nearly every continent has an important tin-mining country. Tin is produced by reducing the ore with coal in a reverberatory furnace. This metal is a relatively scarce element with an abundance in the earth's crust of about 2 ppm, compared with 94 ppm for zinc, 63 ppm for copper, and 12 ppm for lead. Most of the world's tin is produced from placer deposits; at least one-half comes from Southeast Asia. The only mineral of commercial importance as a source of tin is cassiterite (SnO₂), although small quantities of tin are recovered from complex sulfides such as stanite, cylindrite, frankeite, canfieldite, and teallite. Secondary, or scrap, tin is also an important source of the tin.

Isotopes

Tin is the element with the greatest number of stable isotopes (ten). 18 additional unstable isotopes are known.

Precautions

The small amount of tin that is found in canned foods is not harmful to humans. Organotin compounds such as tributyltin oxide are biocides and need to be handled with care.

References

• Los Alamos National Laboratory – Tin (http://periodic.lanl.gov/elements/50.html)

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