Beta carbon nitride

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 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 theoretical material has so far proved impossible to make, by nature carbon and nitrogen will not form a crystalline structure. In 2000 a team at Northwestern University, Illinois claimed to have created atom-thick layers of the material by magnetron sputtering - creating at least partially sp³-bonded crystalline carbon nitrides at the junction of successive layers of titanium nitride and carbon nitride