X-RAY-DIFFRACTION STUDY OF SOLID HYDROGEN-SULFIDE UNDER HIGH-PRESSURE

Solid H2S was studied by x-ray diffraction under pressure up to 20 GPa at room temperature. An F --> P symmetry change in the cubic lattice was observed at 8 GPa. At 11 GPa where a previous Raman study indicate d a pressure-induced transition, an obvious crystal structure change f rom the cubic symmetry to a lower symmetry was observed.