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50
Sn
118.7
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Crystals of cassiterite - SnO2 - tin ore (Photo by Chris Ralph)
| Classification: | Tin can behave as a metal (white tin) |
| or a nonmetal (gray tin). | |
| Atomic weight: | 118.69 g/mol |
| Density @ 20 oC: | 7.30 g/cm3 |
| Atomic volume: | 16.3 cm3/mol |
Solder can be used to secure electronic compotents.
Solder is usually about 60% tin and 40% lead.
Here solder is being removed from a circuit board.
Image by Hugo.
Discovery of Tin
Tin has been known since ancient times. We do not know who discovered it.
The Bronze Age began in about 3000 BC and tin was used in bronze, which contains roughly ninety percent copper and ten percent tin.
The addition of tin to bronze alloys improves their properties compared with pure copper: for example, bronze is harder and more easily cast than copper.
The ancient Greeks obtained their tin by sea-trade and referred to the source as 'The Cassiterides', meaning Tin Islands.
These islands were most likely to have been in Cornwall, Great Britain and/or north-west Iberia, Spain where there are large tin deposits.
In less ancient times, Robert Boyle published a description of his experiments on the oxidation of tin in 1673.
Tin's chemical symbol, Sn, comes from its Latin name, 'stannum.'
States
State (s, l, g): solid
Melting point: 505.078 K (231.928 oC)
Melting point: 505.078 K (231.928 oC)
Boiling point: 2893 K (2620 oC)
Energies
Specific heat capacity: 0.227 J g-1 K-1
Heat of fusion: 7.029 kJ mol-1
1st ionization energy: 708.6 kJ mol-1
3rd ionization energy: 2943 kJ mol-1
Heat of fusion: 7.029 kJ mol-1
1st ionization energy: 708.6 kJ mol-1
3rd ionization energy: 2943 kJ mol-1
Heat of atomization: 302 kJ mol-1
Heat of vaporization: 295.80 kJ mol-1
2nd ionization energy: 1411.8 kJ mol-1
Electron affinity: 107 kJ mol-1
Heat of vaporization: 295.80 kJ mol-1
2nd ionization energy: 1411.8 kJ mol-1
Electron affinity: 107 kJ mol-1
Oxidation & Electrons
Shells: 2,8,18,18,4
Minimum oxidation number: -4
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 1.96
Minimum oxidation number: -4
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 1.96
Electron configuration: [Kr] 4d10 5s2 5p2
Minimum oxidation number: -4
Max. common oxidation no.: 4
Polarizability volume: 7.7 Å3
Minimum oxidation number: -4
Max. common oxidation no.: 4
Polarizability volume: 7.7 Å3
Appearance & Characteristics
Structure: distorted diamond
Hardness: 1.5 mohs
Hardness: 1.5 mohs
Time lapse movie of tin's allotropes. Metallic white tin becomes non-metallic gray tin. This is known as 'tin pest' and is a problem at low temperatures. 1 second of movie equals one hour in real time.
A piece of zinc metal in tin chloride solution. Zinc is more reactive than tin, so zinc chloride forms, replacing the tin chloride. Crystals of pure metallic tin begin to form on the zinc.
Color: silvery-white
Harmful effects:
Tin is considered to be non-toxic but most tin salts are toxic. The inorganic salts are caustic but of low toxicity. Organometallic compounds of tin are highly toxic.
Characteristics:
Tin is a silvery-white, soft, malleable metal that can be highly polished.
Tin has a highly crystalline structure and when a tin bar is bent, a 'tin cry' is heard, due to the breaking of these crystals.
It resists oxygen and water but dissolves in acids and bases. Exposed surfaces form an oxide film. When heated in air, tin forms tin(IV) oxide (stannic oxide) which is feebly acidic.
Tin has two allotropic forms at normal pressure, gray tin and white tin. Pure white tin slowly tends to become the gray powder (gray tin), a change commonly called 'tin pest' at temperatures below 13.2 oC. Gray tin has no metallic properties at all. Commercial quality tins are resistant to tin pest as a result of the inhibiting effects of minor impurities.
Uses:
Tin is used as a coating on the surface of other metals to prevent corrosion. 'Tin' cans, for example, are made of tin-coated steel.
Alloys of tin are commercially important in, for example, soft solder, pewter, bronze and phosphor bronze.
Tin chloride (stannous chloride, SnCl2) is used as a mordant in dyeing textiles and for increasing the weight of silk.
Stannous fluoride (SnF2) is used in some toothpastes.
Harmful effects:
Tin is considered to be non-toxic but most tin salts are toxic. The inorganic salts are caustic but of low toxicity. Organometallic compounds of tin are highly toxic.
Characteristics:
Tin is a silvery-white, soft, malleable metal that can be highly polished.
Tin has a highly crystalline structure and when a tin bar is bent, a 'tin cry' is heard, due to the breaking of these crystals.
It resists oxygen and water but dissolves in acids and bases. Exposed surfaces form an oxide film. When heated in air, tin forms tin(IV) oxide (stannic oxide) which is feebly acidic.
Tin has two allotropic forms at normal pressure, gray tin and white tin. Pure white tin slowly tends to become the gray powder (gray tin), a change commonly called 'tin pest' at temperatures below 13.2 oC. Gray tin has no metallic properties at all. Commercial quality tins are resistant to tin pest as a result of the inhibiting effects of minor impurities.
Uses:
Tin is used as a coating on the surface of other metals to prevent corrosion. 'Tin' cans, for example, are made of tin-coated steel.
Alloys of tin are commercially important in, for example, soft solder, pewter, bronze and phosphor bronze.
Tin chloride (stannous chloride, SnCl2) is used as a mordant in dyeing textiles and for increasing the weight of silk.
Stannous fluoride (SnF2) is used in some toothpastes.
Reactions & Compounds
Reaction with air: mild, w/ht ⇒ SnO2
Reaction with 15 M HNO3: mild, ⇒ SnO2, NOx
Oxide(s): SnO , SnO2 (stannic oxide)
Hydride(s): SnH4, Sn2H6
Reaction with 15 M HNO3: mild, ⇒ SnO2, NOx
Oxide(s): SnO , SnO2 (stannic oxide)
Hydride(s): SnH4, Sn2H6
Reaction with 6 M HCl: none
Reaction with 6 M NaOH: mild, ⇒ H2, [Sn(OH6)]2-
Chloride(s): SnCl2 & SnCl4
Reaction with 6 M NaOH: mild, ⇒ H2, [Sn(OH6)]2-
Chloride(s): SnCl2 & SnCl4
Radius
Atomic radius: 140.5 pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): pm
Ionic radius (1+ ion): pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Conductivity
Thermal conductivity: 66.8 W m-1 K-1
Electrical conductivity: 8.7 x 106 S m-1
Abundance & Isotopes
Abundance earth's crust: 2.3 parts per million by weight, 0.4 parts per million by moles
Abundance solar system: 9 parts per billion by weight, 0.1 parts per billion by moles
Cost, pure: $24 per 100g
Cost, bulk: $1.80 per 100g
Source: Tin very rarely occurs free in nature. The chief ore is cassiterite (SnO2). The metal is prepared from cassiterite by reducing the ore with coal.
Isotopes: Tin has 35 isotopes whose half-lives are known, mass numbers 100 to 134. Of these, ten are stable: 112Sn, 114Sn, 115Sn, 116Sn, 117Sn, 118Sn, 119Sn, 120Sn, 122Sn and 124Sn. The most abundant is 118Sn at 24%.
Abundance solar system: 9 parts per billion by weight, 0.1 parts per billion by moles
Cost, pure: $24 per 100g
Cost, bulk: $1.80 per 100g
Source: Tin very rarely occurs free in nature. The chief ore is cassiterite (SnO2). The metal is prepared from cassiterite by reducing the ore with coal.
Isotopes: Tin has 35 isotopes whose half-lives are known, mass numbers 100 to 134. Of these, ten are stable: 112Sn, 114Sn, 115Sn, 116Sn, 117Sn, 118Sn, 119Sn, 120Sn, 122Sn and 124Sn. The most abundant is 118Sn at 24%.
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