Carbon nitrides, very high pressure chemical

Ceramics are crystalline in nature, with a dearth of free electrons. They have a high electrical resistivity, are very stable, chemically and thermally, and have a high melting point. They are formed by the bonding of a metal and a nonmetal and may exist as oxides, nitrides, carbides, or silicides. An exception is diamond, which consists of pure carbon subjected to high temperature and pressure. Diamond substrates meet the criteria for ceramics and may be considered as such in this context. 

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