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Calcium carbide
General
Systematic name Calcium Carbide
Other names
Molecular formula CaC2
Molar mass 64.1 g/mol
Appearance gray-black Crystals
Crystal Structure orthorhombic
CAS number 75-20-7
Properties
Density and phase 2.22 g/cm3
Melting point 2300 °C
Boiling point
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Chemical infobox

Calcium carbide is a chemical compound with the chemical formula CaC2. It has the appearance of grayish white lumps.

Calcium carbide is produced by electrostatic discharge through a mixture of lime and carbon at high temperature. The compound reacts vigorously with water to form acetylene. This reaction is the basis of the industrial manufacture of dissolved acetylene (DA), and the only modern industrial use for calcium carbide.

Calcium carbide is used in carbide lamps, in which water drips on carbide and the formed acetylene is ignited. The lamps found extensive use in coal mines, but most have now been replaced by electric lamps. Carbide lamps are still used by some cavers exploring caves and other underground areas. They were also used extensively as head lights in early automobiles; this application is also obsolete, them having been replaced entirely by electric lamps.

It is still used in the Netherlands and Belgium for a traditional custom called Carbidschieten (Shooting Carbid).

The reaction of calcium carbide with water was discovered by Friedrich Wohler in 1862. The equation is:

CaC2 + 2 H2O → C2H2 + Ca(OH)2
Therefore, 1 gram of CaC2 gives 349ml of acetylene.

Together with calcium phosphide, calcium carbide is used in floating, self-igniting naval signal flares (see Holmes' Marine Life Protection Association).

Calcium Carbide is also used in small carbide lamps called "Carbide Candles", which are used for blackening rifle sights to reduce glare. These "candles" are used due to the sooty flame produced by acetylene.

External links


Carbides | Calcium compounds

Kalziumcarbid | Carburo de calcio | Karbit | Kalcium-karbid | Calciumcarbide | Карбид кальция

 

This article is licensed under the GNU Free Documentation License. It uses material from the "Calcium carbide".

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