Tin (Sn) is a corrosion-resistant non-toxic low-melting metal, which determines its application in the food and electronics industries. In addition, Sn is a component of many alloys. This page contains a description of this material: physical and chemical properties, application areas, grades, and types of products.
Basic information
Tin (Sn, Stannum) is a chemical element with atomic number 50 in the periodic table. It belongs to the group of light metals; it’s malleable and plastic material. It has a silvery-white color with a shiny surface. The density is 7.31 g/cm3, the melting point is 231.9 °C, the boiling point is 2620 °C.
The metal can exist in three modifications depending on the temperature:
α-Sn (grey tin) - temperature below 13.2 °C; cubic crystal lattice of diamond type;
It is worth noting that at an ambient temperature below 13.2 °C, tin changes its phase state and passes into the α-modification. In this case, it cracks and turns into a powder. The highest transition rate is observed at a temperature of -33 °C. This phenomenon is called "tin plague".
In earth crust, the content of Sn according to various data is from 2·10-4 to 8·10-3% by weight. This metal is the 47th most common in earth crust. The main mineral containing tin is cassiterite (tin stone), which contains up to 78.8% of Sn. China, Indonesia, Malaysia and Thailand are the leaders in the reserves of the considered chemical element.
History of discovery
The described metal is known to humanity since ancient times. It is believed that its use began in the IV millennium BC. The greatest spread in the ancient world was in the bronze age (approximately XXXV-XI centuries BC), because Sn is one of the main components of tin bronze. The name “tin” was established to this chemical element in the fourth century.
Tin properties
Physical properties
Property
Value
Atomic number
50
Atomic mass, u
118,7
Atom radius, pm
162
Density, g/cm³
7,31
Thermal conductivity, W/(m·K)
66,8
Melting point, °С
231,9
Boiling point, °С
2620
Heat of fusion, kJ/mol
7,07
Heat of evaporation, kJ/mol
296
Molar volume, см³/mol
16,3
Group of metals
Light metal
Chemical properties
Property
Value
Covalent radius, pm
141
Ion radius, pm
(+4e) 71 (+2) 93
Electronegativity (according to Pauling)
1,96
Electrode potential
-0,136
Oxidation degree
+4, +2
Ionization energy, kJ/mol (eV)
708,2 (7,34)
Tin grades
The metal is produced in several grades in industrial scale:
OVCH-000 - tin of high purity, the content of Sn is 99.999%; it is produced in the form of blanks and rods.
O1pch, O1 - the content of Sn is 99.915% and 99.900%, accordingly; it is produced in the form of blanks, rods, wire.
O2 - 99.565% of Sn; semi-finished products: blank, wire, rod.
O3 - 98.49% of Sn in the compound, the most significant impurity is Pb - 1.0%; supplied in the form of blanks.
O4 - tin with the highest content of impurities, their total amount is 3.51%, the mass fraction of Sn is 96.43%; produced in the form of blanks.
Advantages/disadvantages
Advantages:
it has good corrosion resistance in the environment of organic acids and salts;
it is not affected by the negative influence of sulfur contained in plastics;
non-toxic, which allows to use it in the food industry.
Disadvantages:
it has a low melting point;
tendency to "tin plague".
Tin application
Sn has several main application areas. Due to its non-toxicity and resistance to corrosion in the environment of organic salts and acids, this metal has become widespread in the food industry. It is applied in the form of coatings on various products that have contact with food. Tin is also used to cover copper wire cores. It protects Cu from negative effects of S contained in the rubber insulation.
In the production of electronic devices, where soldering is very often used to connect elements, tin is used as a solder.
Sn is a component of a large number of alloys with copper, zinc, copper and zinc, copper and antimony. Babbitts and bronzes are among the most popular.
Tin products
Modern industry produces a variety of tin products. The most common are blanks, wire, rods and anodes.
Tin anodes, which are used for tinning the surfaces of various products, are widely used in industry. Tin wire and rods are often used as solders in electronics when soldering. Tin blanks are the starting material for the production of other semi-finished products. They are also used in the smelting of alloys containing tin.