Pressure-induced polymerization of P(CN)(3)

Motivated to explore the formation of novel extended carbon-nitrogen solids via well-defined molecular precursor pathways, we studied the chemical reactivity of highly pure phosphorous tricyanide, P(CN)(3), under conditions of high pressure at room temperature. Raman and infrared (IR) spectroscopic measurements reveal a series of phase transformations below 10 GPa, and several low-frequency vibrational modes are reported for the first time. Synchrotron powder X-ray diffraction measurements taken during compression show that molecular P(CN)(3) is highly compressible, with a bulk modulus of 10.0 +/- 0.3 GPa, and polymerizes into an amorphous solid above similar to 10.0 GPa. Raman and IR spectra, together with first-principles molecular-dynamics simulations, show that the amorphization transition is associated with polymerization of the cyanide groups into CN bonds with predominantly sp(2) character, similar to known carbon nitrides, resulting in a novel phosphorous carbon nitride (PCN) polymeric phase, which is recoverable to ambient pressure. (C) 2015 AIP Publishing LLC.