Bismuth (83)[Bi
Chemical formula: Bi
Atomic number: 83
Series: Metal
Appearance: Shiny silvery white
Mass fraction of earth: 0.2 ppm
Physical state: Solid
Density: 9.78 g/cm3
Melting point: 271.3°C
Boiling point: 1560°C
Mohs hardness: 2.5
Molar volume: 21.31-10?6 m3 / mol
Heat of melting: 10.90 kJ / mol
Heat of vaporization: 179 kJ / mol
Physical and chemical properties
Bismuth is a silvery-white, relatively soft and coarsely crystalline heavy metal
or semimetal. It exhibits a rhombic crystal structure with very tightly packed
bilayers. The shortest distance between two bilayers is 352.9 pm, which is only
15% greater than the minimum distance between two atoms in a bilayer.
It is one of the few heavy metals that is relatively non-toxic and has the
strongest Hall effect of all the metallic elements. It also has the strongest
anti-magnetic properties of any metal. That is, it is pushed out of externally
applied magnetic fields.
Liquid bismuth has an unusual density and is one of the few substances that
expand when solidified. This phenomenon can also be observed for gallium,
silicon, germanium, p, tellurium and water. In the case of bismuth, it is based
on the fact that a "double" phase transition takes place during melting and
solidification.
Bismuth is stable in dry air at room temperature. In humid air, an oxide layer
is formed on the surface. The heavy metal is resistant to water and
non-oxidizing acids. In oxidizing acids, bismuth dissolves and forms bismuth
salts. In powder form, it is a flammable solid. The compact form of the metal is
not flammable.
In the red-hot state, it is burned with a blue flame into brownish-yellow smoke,
i.e. bismuth(III) oxide.
The use
Today, bismuth is mainly used to produce metal alloys with low melting
temperatures.
The metal of wood can be produced by melting together 50% of bismuth, 25% of
lead, 12.5% of tin and 12.5% of cadmium. This alloy melts at about 70°C. It is
used as a substitute for fuses or lead in soft solder, heating baths or
automatic fire alarms and sprinklers. The bismuth-bismol alloy with bismuth and
manganese is a strong permanent magnet.
Due to its low melting temperature, liquid bismuth is also used as a coolant in
nuclear reactors. The chemical industry uses bismuth as a catalyst. Bismuth
telluride Bismuth Bi2Te3 produces cold in the Peltier element.
Bismuth is also used in the chemical industry, in the production of cosmetics
and in medicine.
Most of bismuth is used in the production of pharmaceutical bismuth
preparations. For example, bismuth nitrite has disinfectant, deodorant and
hemostatic properties.
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