Silicon carbide structure

Three main types of silicon carbide polymorph

There are about 250 crystalline forms of silicon carbide. Because silicon carbide has a series of homogeneous polytypes with similar crystal structure, silicon carbide has the characteristics of homogeneous polycrystalline.

Silicon carbide (Mosanite) is very rare on Earth, but it is quite common in space. Cosmic silicon carbide is usually a common component of the cosmic dust around carbon stars. The silicon carbide found in space and meteorites is almost invariably β-phase crystalline.

A-sic is the most common of these polytypes. It is formed at temperatures greater than 1700°C and has a hexagonal crystal structure similar to wurtzite.

B-sic, which has a diamond-like sphalerite crystal structure, is formed at less than 1700°C.