Fig. 78: Ratio of the S1/2, 1/2, 1/2 d-spacing and its ideal value (4 x d222) versus pressure. The different symbols correspond to measurements from different samples. Upper inset: single-crystal energy-dispersive spectra of the (222) reflection at 9 GPa and 170 GPa. The (111) and S1/2, 1/2, 1/2 reflections are clearly visible. Lower inset: evolution of the S1/2, 1/2, 1/2 intensity with pressure, relative to the (222) (not corrected for the spectral distribution of the wiggler).