What is "beta carbon nitride"

n. (context chemistry English) a theoretical binary compound of carbon and nitrogen, C₃N₄, that is thought would have properties similar to diamond or boron nitride

Beta carbon nitride (β-CN) is a superhard material predicted to be harder than diamond.

The material was first proposed in 1985 by Marvin Cohen and Amy Liu. Examining the nature of crystalline bonds they theorised that carbon and nitrogen atoms could form a particularly short and strong bond in a stable crystal lattice in a ratio of 1:1.3. That this material would be harder than diamond on the Mohs scale was first proposed in 1989.

The material has been considered difficult to produce and could not be synthesized for many years. Recently, the production of beta carbon nitride was achieved. For example, nanosized beta carbon nitride crystals and nanorods of this material were prepared by means of an approach involving mechanochemical processing.