GaP at ultrahigh pressure

An x-ray diffraction experiment has been carried out on GaP compressed in a quasi-hydrostatic pressurizing medium to 296 ± 5 kbar. The transformation pressure was found to be increased from the value of 220 kbar (22 GPa) reported in a less hydrostatic environment, since two phases of GaP (I and II) were found in coexistence at 250 ± 5 kbar. No evidence of disproportionation was found at this pressure, or 296 kbar, where sharp lines of phase II were found (body centered tetragonal). No evidence of amorphization was found on release of pressure.