Raman spectroscopy and X‐ray diffraction of pressure‐induced reversible structure change in K2OsO2(OH)4

Abstract

AbstractHigh‐pressure structural evolution of K2OsO2(OH)4, a potassium osmate dihydrate, has been studied by high‐pressure Raman spectroscopy and angle dispersive X‐ray diffraction. A pressure‐induced reversible structure change is observed at approximately 8 GPa, evidenced by the splitting of Raman modes and the addition of X‐ray diffraction peaks. The splitting of phonon generally occurs in the Raman modes with smaller Grüneisen parameters. The pressure‐induced structural change is correlated with the relatively isolated arrangement of Os–O polyhedron. In addition, the zero‐pressure bulk modulus B0 = 46(1) GPa and zero‐pressure Grüneisen parameters γ of K2OsO2(OH)4 are given and discussed.