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Carborundum

Silicon carbide
Sample of silicon carbide as a boule
Names
Preferred IUPAC name
Silicon carbide
Other names
Carborundum
Moissanite
Identifiers
409-21-2 YesY
3D model (Jmol) Interactive image
ChEBI CHEBI:29390 YesY
ChemSpider 9479 YesY
ECHA InfoCard 100.006.357
EC Number 206-991-8
13642
MeSH Silicon+carbide
PubChem 9863
RTECS number VW0450000
Properties
CSi
Molar mass 40.10 g·mol−1
Appearance Yellow to green to bluish-black, iridescent crystals
Density 3.21 g·cm−3 (all polytypes)
Melting point 2,730 °C (4,950 °F; 3,000 K) (decomposes)
Electron mobility ~900 cm2/V·s (all polytypes)
−12.8·10−6 cm3/mol
2.55 (infrared; all polytypes)
Hazards
Not listed
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
US health exposure limits (NIOSH):
PEL (Permissible)
 TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp)
REL (Recommended)
 TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)
IDLH (Immediate danger)
 N.D.
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

Silicon carbide (SiC), also known as carborundum /kɑːrbəˈrʌndəm/, is a compound of silicon and carbon with chemical formula SiC. It occurs in nature as the extremely rare mineral moissanite. Synthetic silicon carbide powder has been mass-produced since 1893 for use as an abrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and detectors in early radios were first demonstrated around 1907. SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both. Large single crystals of silicon carbide can be grown by the Lely method; they can be cut into gems known as synthetic moissanite. Silicon carbide with high surface area can be produced from SiO2 contained in plant material.

Non-systematic, less-recognized, and often unverified syntheses of silicon carbide include

Wide-scale production is credited to Edward Goodrich Acheson in 1890. Acheson was attempting to prepare artificial diamonds when he heated a mixture of clay (aluminum silicate) and powdered coke (carbon) in an iron bowl. He called the blue crystals that formed carborundum, believing it to be a new compound of carbon and aluminum, similar to corundum. In 1893, Henri Moissan discovered the very rare naturally occurring SiC mineral while examining rock samples found in the Canyon Diablo meteorite in Arizona. The mineral was named moissanite in his honor. Moissan also synthesized SiC by several routes, including dissolution of carbon in molten silicon, melting a mixture of calcium carbide and silica, and by reducing silica with carbon in an electric furnace.


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