Bond strengths of New Carbon-nitride-Related material C₂N₂(CH₂)

A new carbon-nitride-related material C₂N₂(CH₂) nanopletelet was synthesized by subjecting a precursor C₃N₄H_xO_y+Au in a laser-heating diamond anvil cell (LHDAC) to the pressure of 40 GPa and the temperature of 1200-2000 K. The synthesized C₂N₂(CH₂) was accordingly found to be an orthorhombic unit cell of the space group Cmc2₁ with lattice constants a = 7.625Å, b = 4.490Å, and c = 4.047Å. The bulk modulus B₀ was determined to be B0 = 258 ± 3.4 GPa, only the 60 % that of the diamond. C₂N₂(CH₂) consists of the tetrahedrally coordinated C with three C-N single bond and the one C-C single bond, and the bridging carbon with the C-CH₂-C bond. The C-N single bond length of the tetrahedron ranges from 1.444 to 1.503 Å. This bond length is close to the C-N single bond of 1.447 to 1.458 Å in the superhard β-C₃N₄. The compressibility of the C-N and C-C single bond of C₂N₂(CH₂) ranges from 0.976 to 0.982 with the pressure of 30 GPa. These values are very close to the compressibility of the C-N and C-C single bond of 0.978 to 0.982 in β-C₃N₄, cubic-C₃N₄, and diamond.