X-ray diffraction experiments have been carried out on germanium in a diamond anvil cell to 26 GPa. The pressure at the transition to the metallic phase (II) has been studied in different pressurizing media, giving 10.6±0.05 GPa in a quasihydrostatic medium (4:1 methanol:ethanol mixture), 9.8±0.1 GPa in NaCl, and 8.1±0.3 GPA when the sample was compressed directly between the anvils. The compression curve for phase II has been fitted to a modified Murnaghan equation. Upon release of pressure the transformation from phase II to III (tetragonal) was found at 7.6±0.05 GPa. It was found that the details of the transition depended on the stress condition and rate of decompression.

• Received 13 January 1986

DOI:https://doi.org/10.1103/PhysRevB.34.362