No experimental thermodynamic data are available at the moment for the solid C3N4. Theoretical calculations suggest that β-C3N4 could have a bulk modulus comparable to that of diamond. Its cohesive energy can be obtained either from ab initio quantum calculations or starting from bond enthalpies derived from data for organic compounds. The entropy and heat capacity of the material can be obtained by means of the Debye statistical theory. It is estimated that pressures of the order of tens or even hundreds of GPa are needed in order to obtain the higher energy cubic β phase instead of other lower energy polymorphs.
