sodium carbide is a black or gray powder that has a chemical formula of CaC2. Its main use is in the manufacture of the flammable gas acetylene.
Calcium Carbide is prepared industrially from calcium and carbon at high temperatures, usually 2,000 degC ( 3,600 degF). It also reacts with nitrogen gas at elevated temperatures to form a fertilizer called calcium cyanamide, CaCN2.
Boron carbide is another boron-rich material, which is used in the nozzles of sandblasters. It is a hard ceramic material with an unusual structure that includes icosahedral boron units linked by carbon atoms.
Interstitial carbides are derived from relatively large transition metals that act as host lattices for small carbon atoms that occupy the interstices of the close-packed atomic radii. Generally, the interstices are cubic or hexagonal in the case of rock salt.
These carbides are hard and brittle, but they retain the properties of the metal, including conductivity of heat and electricity and metallic lustre. They are also refractory, meaning that they resist heat and cold.
In addition to its industrial uses, calcium carbide is one of the most important sources of acetylene, which is used as an inexpensive and abundant fuel in countries where it is difficult or costly to obtain petroleum. This is because water and calcium carbide react together to produce acetylene, which burns at a much higher temperature than does gasoline.
Other types of carbide include tungsten carbide, which is found in tools, ball point pens, razor blades and jewelry; and zirconium carbide, which is a hard refractory ceramic with an extremely high resistance to corrosion. The latter is also a key ingredient in the making of tool bits and cutting tools, as well as cladding and cermets.