Pressure-induced phase transitions in AgClO4

TL;DR

This study investigates pressure-induced structural phase transitions in AgClO4 using experimental x-ray diffraction and density functional theory, revealing a transition at 5.1 GPa and proposing another beyond 17 GPa.

Contribution

It provides the first combined experimental and theoretical analysis of AgClO4's phase transitions under pressure, including structural details and phonon behavior.

Findings

Structural transition from tetragonal to orthorhombic at 5.1 GPa

Theoretical prediction of a second transition beyond 17 GPa

Equation of state and phonon pressure evolution reported

Abstract

AgClO4 has been studied under compression by x-ray diffraction and density functional theory calculations. Experimental evidence of a structural phase transition from the tetragonal structure of AgClO4 to an orthorhombic barite-type structure has been found at 5.1 GPa. The transition is supported by total-energy calculations. In addition, a second transition to a monoclinic structure is theoretically proposed to take place beyond 17 GPa. The equation of state of the different phases is reported as well as the calculated Raman-active phonons and their pressure evolution. Finally, we provide a description of all the structures of AgClO4 and discuss their relationships. The structures are also compared with those of AgCl in order to explain the structural sequence determined for AgClO4.