Fig. 4: Diffraction patterns (in arbitrary units) of solid products formed from shocked benzene at 55 GPa, 4940 K.

A Expanded region between d = 2.5 and 3.8 Å shows the measured low-angle peaks (solid lines) and fits (dashed lines) relative to the estimated range of d-spacings for graphitic layered carbon structures at the same P–T conditions (gray shaded region) and the range of predicted d-spacings for graphate I–IV and H₁₈ at 50 GPa and ambient T (red shaded region). B Full range of the measured diffraction exhibiting multiple peaks that do not index to graphite or diamond forms, particularly in the regions of 2.4–2.8 and 3.4–3.6 Å⁻¹. Dotted lines correspond to estimated graphite reflections, dashed lines to cubic diamond reflections at 55 GPa and 5000 K. Calculated diffraction patterns for graphate-I, and -II from Wen et al. ⁴⁶, and H₁₈ calculated at 50 GPa and ambient T are shown for comparison⁴⁷.