Crystals

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General Information

Silicon Carbide

Silicon carbide is also known as carborundum. It can rarely be found in nature as moissanite, almost all of the silicon carbide on this planet is synthetic. It can be produced with many different types of crystal structures, usually it's polymorf (alpha silicon carbide).[1]

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Production Methods

Silicon carbide can be produced by combining silicon and carbon at high temperatures in an Acheson graphite electric resistance furnace. This a process type called pyrolysis. It can also be produced with the Lely process, which is a vapor deposition technique using silicon carbide powder to get very pure crystals.[1]

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Chemical & Physical Information

Trivial NameCarborundum
Chemical NameSilicon Carbide
Other namesCarborundum (EN,NL,BE)
Type of chemicalCovalent compound
Chemical FormulaSiC
CAS number409-21-2
Crystal systemHexagonal (most common)
Bravais latticeRhombohedral
Coordination geometryOctahedral
Hardness (Mohs)9.5
Young's modulus400-700 GPa
ColourBlack, blue, green
LusterMetallic
StreakGreenish gray
OpacityOpaque to translucent and transparent.
Safety summarySafe
Safety dataMSDS
Production methodPyrolysis, vapor deposition.
StorageNothing special.
ExtraUsed for drills and saw blades.
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Photos

Silicon Carbide

(5 cm)

Silicon Carbide

(1 mm)

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Sources

[1] Wikipedia

[2] Specimen from my personal collection, photo taken by me.