Tin Facts (Atomic Number 50 or Sn)

Tin is silver or gray metal with atomic number 50 and element symbol Sn. It is known for its use for early canned goods and in the manufacture of bronze and pewter. Here is a collection of tin element facts.

Tin Basic Facts

Tin has been known since ancient times. The first tin alloy to gain widespread use was bronze, an alloy of tin and copper. Humans knew how to make bronze as early as 3000 BCE.

Word Origin: Anglo-Saxon tin, Latin stannum, both names for the element tin. Named after Etruscan god, Tinia; denoted by the Latin symbol for stannum.

Isotopes: Many isotopes of tin are known. Ordinary tin is composed of ten stable isotopes. Twenty-nine unstable isotopes have been recognized and 30 metastable isomers exist. Tin has the greatest number of stable isotopes of any element, due to its atomic number, which is a "magic number" in nuclear physics.

Properties: Tin has a melting point of 231.9681°C, boiling point of 2270°C, specific gravity (gray) of 5.75 or (white) 7.31, with a valence of 2 or 4. Tin is a malleable silvery-white metal which takes a high polish. It possesses a highly crystalline structure and is moderately ductile. When a bar of tin is bent, the crystals break, producing a characteristic 'tin cry'. Two or three allotropic forms of tin exist. Gray or a tin has a cubic structure. Upon warming, at 13.2°C gray tin changes to white or b tin, which has a tetragonal structure. This transition from the a to the b form is termed the tin pest. A g form may exist between 161°C and the melting point. When tin is cooled below 13.2°C, it slowly changes from the white form to the gray form, although the transition is affected by impurities such as zinc or aluminum and can be prevented if small amounts of bismuth or antimony are present. Tin is resistant to attack by sea, distilled, or soft tap water, but it will corrode in strong acids, alkalis, and acid salts. The presence of oxygen in a solution accelerates the rate of corrosion.

Uses: Tin is used to coat other metals to prevent corrosion. Tin plate over steel is use to make corrosion-resistant cans for food. Some of the important alloys of tin are soft solder, fusible metal, type metal, bronze, pewter, Babbitt metal, bell metal, die casting alloy, White metal, and phosphor bronze. The chloride SnCl·H₂O is used as a reducing agent and as a mordant for printing calico. Tin salts may be sprayed onto glass to produce electrically conductive coatings. Molten tin is used to float molten glass to produce window glass. Crystalline tin-niobium alloys are superconductive at very low temperatures.

Sources: The primary source of tin is cassiterite (SnO₂). Tin is obtained by reducing its ore with coal in a reverberatory furnace.

Toxicity: Elemental tin metal, its salts, and its oxides present low toxicity. Tin-plated steel cans are still widely used for food preservation. Exposure levels of 100 mg/m³ are considered immediately dangerous. Legal permissible exposure from contact or inhalation is typically set around 2 mg/m³ per 8-hour work day. In contrast, organotin compounds are highly toxic, on par with that of cyanide. Organotin compounds are used to stabilize PVC, in organic chemistry, to make lithium ion batteries, and as biocidal agents.

Tin Physical Data

• Element Classification: Metal
• Density (g/cc): 7.31
• Melting Point (K): 505.1
• Boiling Point (K): 2543
• Appearance: silvery-white, soft, malleable, ductile metal
• Atomic Radius (pm): 162
• Atomic Volume (cc/mol): 16.3
• Covalent Radius (pm): 141
• Ionic Radius: 71 (+4e) 93 (+2)
• Specific Heat (@20°C J/g mol): 0.222
• Fusion Heat (kJ/mol): 7.07
• Evaporation Heat (kJ/mol): 296
• Debye Temperature (K): 170.00
• Pauling Negativity Number: 1.96
• First Ionizing Energy (kJ/mol): 708.2
• Oxidation States: 4, 2
• Lattice Structure: Tetragonal
• Lattice Constant (Å): 5.820

Sources

• Emsley, John (2001). "Tin". Nature's Building Blocks: An A–Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 445–450. ISBN 0-19-850340-7.
• Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0-7506-3365-4.
• Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.