Layered nitride materials in the form of Carbon nitride (C3N4) was speculatedudnearly 22 years ago. It has various structural forms ranging from layered graphiticudto superhard structures. Using first principles calculations based on density functionaludtheory, the structural and elastic properties of these phases are determined.udElastic constants, bulk and shear moduli of cubic phases are compared to that ofuddiamond. From the work it is evident that, although the compressibility of someudof the superhard phases may be better than diamond, the shear modulus indicatesudthat C3N4 is not harder than diamond in contrast to what has been speculated ealier.udThe graphitic hexagonal, rhombohedral as well orthorhombic phases are soft as indicatedudby their bulk and shear moduli, which are similar to that of graphite. Otherudelastic properties such as the Young modulus and Poisson’s ratio as well as theudRaman and infrared vibrational frequencies are also presented in this dissertation
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