Equation of state and phase stability of turbostratic carbon nitride

The lattice parameters of turbostratic carbon nitride (t-CN) have been measured to 20 GPa at room temperature using energy-dispersive X-ray powder diffraction with synchrotron radiation. A fit to the experimental p-V data using Birch-Murnaghan equation of state gives values of the t-CN bulk modulus 20.1(5) GPa and its pressure derivative 8.3(2). These values point to a significantly higher compressibility of turbostratic carbon nitride as compared to turbostratic graphite. In the 4.7-17.8 GPa range the onset temperature of t-CN decomposition increases from 990(10) to 1850(50) K. The decomposition results in the formation of disordered graphite at pressure below 8 GPa, and diamond at higher pressures.