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Oxidation & Electrons | Appearance & Characteristics Reactions | Compounds | Radius | Conductivity Abundance & Isotopes 
Crystals of cassiterite - SnO2 - tin ore (Photo by Chris Ralph) |
General:
| Name: Tin | Symbol: Sn |
| Type: Metal, Carbon group | Atomic weight: 118.69 |
| Density @ 293 K: 7.30 g/cm3 | Atomic volume: 16.3 cm3/mol |
| Discovered: Tin has been known since ancient times. Its chemical symbol, Sn, comes from its Latin name, 'stannum'. | |
States
| State (s, l, g): solid | |
| 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 atomization: 302 kJ mol-1 |
| Heat of fusion: 7.029 kJ mol-1 | Heat of vaporization: 295.80 kJ mol-1 |
| 1st ionization energy: 708.6 kJ mol-1 | 2nd ionization energy: 1411.8 kJ mol-1 |
| 3rd ionization energy: 2943 kJ mol-1 | Electron affinity: 107 kJ mol-1 |
Oxidation & Electrons
| Shells: 2,8,18,18,4 | Electron configuration: [Kr] 4d10 5s2 5p2 |
| Minimum oxidation number: -4 | Maximum oxidation number: 4 |
| Min. common oxidation no.: 0 | Max. common oxidation no.: 4 |
| Electronegativity (Pauling Scale): 1.96 | Polarizability volume: 7.7 Å3 |
Appearance & Characteristics
| Structure: distorted diamond | Color: silvery-white |
| Hardness: 1.5 mohs | |
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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
| Reaction with air: mild, w/ht ⇒ SnO2 | Reaction with 6 M HCl: none |
| Reaction with 15 M HNO3: mild, ⇒ SnO2, NOx | Reaction with 6 M NaOH: mild, ⇒ H2, [Sn(OH6)]2- |
Compounds
| Oxide(s): SnO , SnO2 (stannic oxide) | Chloride(s): SnCl2 & SnCl4 |
| Hydride(s): SnH4, Sn2H6 |
Radius
| Atomic radius: 140.5 pm | Ionic radius (1+ ion): pm |
| Ionic radius (2+ ion): pm | Ionic radius (3+ ion): pm |
| Ionic radius (2- 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: $8 per 100g | |
| Cost, bulk: $0.83 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: 35 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%. | |
