Calcium carbide
Encyclopedia : C : CA : CAL : Calcium carbide
| 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 infoboxInfobox disclaimer and references] | |
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 The lamps found extensive use in coal mines, but most have now been replaced by electric lamps.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
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
- For a full list of external links to MSDSs, spectroscopic data, commercial chemicals suppliers etc. for this compound, see [Chemical sources].
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