Fig. 2. Collection of PXRD patterns of 1 and 2 recorded at ambient pressure (blue and purple) and at high pressure (orange and red). Diffractograms were recorded using a monochromatic X-ray beam with λ = 0.41334 Å. Simulated diffraction patterns for the room temperature op and low temperature cp phases of 1 (taken from ref. 37) are shown for comparison (black and green). The broad hump in the background of the experimental patterns is attributed to diffuse scattering from the pressure transmitting fluid. The patterns have been normalised and offset vertically for clarity.