High-Pressure Structural Behavior of para-Xylene

A high-pressure neutron powder diffraction study was conducted on perdeuterated para-xylene (C8D10). para-Xylene crystallizes in the monoclinic crystal system (space group P2(1)/n) at ambient temperature and ca. 0.1 GPa. The structure is consistent with the known low-temperature form. No further phase transitions were observed in the pressure range 0.11(1)-4.72(2) GPa. A complementary high-pressure single-crystal diffraction experiment was performed on hydrogenous para-xylene confirming the assigned space group P2(1)/n. An isothermal equation of state was obtained [bulk modulus, B-0 = 3.5(4) GPa] and structural changes of the material have been investigated as a function of pressure. This experimental study is supported by dispersion-corrected density functional theory calculations.

Automated summary

A high-pressure neutron powder diffraction study and density functional theory calculations were conducted to investigate the structure and properties of perdeuterated para-xylene. The results demonstrate that para-xylene crystallizes in the monoclinic crystal system at low temperature, and the structural changes under pressure are minimal.