Experimental Observation of Phase Transition in Sb ₂ O ₃ under High Pressure

Abstract

The in situ high-pressure behavior of the semiconductor antimony trioxide (Sb2O3) is investigated by the Raman spectroscopy techniques and angle-dispersive synchrotron x-ray powder diffraction in a diamond anvil cell up to 31.5 and 30.7 GPa, respectively. New peaks observed in the external lattice mode range in the Raman spectra at 13.5 GPa suggest that the structural phase transition occurs. The group mode (140 cm −1 ) in Sb2O3 exhibits anomalous pressure dependence; that is, the frequency decreases gradually with the increasing pressure. High pressure synchrotron x-ray diffraction measurements at room temperature reveal that the transition from the orthorhombic structure to high-pressure new phase occurs at about 14.2 GPa, corresponding to the softening of the group optic mode (140 cm −1 ).

Pressure-Induced Phase Transitions in Sesquioxides

“…HP studies of β-Sb 2 O 3 revealed a 1st-order PT around 15 GPa [246,247]. Nevertheless, the nature of its HP phase is still under debate.…”

High-pressure synchrotron x-ray diffraction and Raman spectroscopic study of plumbogummite

“…XRD and Raman spectroscopy are powerful techniques for exploring structural and vibrational properties. [9][10][11][12][13] Several XRD and/or Raman investigations of [PO 4 ] 3− -containing minerals have appeared in the literature. [14,15] For exam-ple, high-pressure Raman scattering was employed to determine the changes in the structure and pressure coefficients of the phosphate modes in Ba 3 (PO 4 ) 2 , Sr 3 (PO 4 ) 2 , and K 2 MgWO 2 (PO 4 ) 2 .…”